Posts Tagged ‘calcium’

The Post – Fiddler Babies Thrive in the “White Cloud.”

March 30, 2008

The white cloud in the babies’ tank continues, yet the water quality is GREAT.

What mystifies me is the absolute ?attraction the fiddler babies have for the aragonite sand and the reef rock. They swarm all over areas of the sand, stirring up clouds of dust, and bouncing down against the aragonite sand, then move on to another area. They are equally attracted to the reef rock, which is nothing more than a hunk of petrified coral.

On the flip side, while they swim by the live rock, they do not seem to be interested in it to any great extent, even though there is a wide variety of algae growing all over it.

The aragonite sand is Seachem’s Meridian Marine Tidal Substrate. The reef rock is “Carib Sea Reef Rock.” Both products help to maintain proper pH and calcium levels, as well as encourage the growth of coralline algae and beneficial bacteria. In fact, I suspect it is the cloud of aragonite dust in the water that may have helped spur the bacteria on, resulting in the nitrite levels in the tank dropping to zero. It just seems counterintuitive to me, to have a tank of water I can barely see through, yet have it be so healthy by the numbers.

I shine the flashlight in the tank and can see thousands of babies swimming around, digging in the sand, or clustering on the reef rock. All are in motion, so they are most definitely alive. I have to wonder if there are already lots of microscopic algae on the surfaces of the sand and the reef rock, and the congregating of the fiddler babies is about eating what’s there.

I am currently feeding them 4 drops of Wardley’s Essentials Small Fry Liquid Food and a 1/4 tsp of Kent Marine’s ZooPlex, 3 times a day. I’m being very careful not to overfeed, and monitoring ammonia and nitrite levels 2-3 times a day.

I’ve also started the live brine shrimp hatchery going, though I have to say, I’m not sure if that’s something I want to deal with on a regular basis. Just one more job I have to do and as one of the sites mentioned, if you can’t get live food, frozen brine shrimp is the next best thing. I know I saw cubes of frozen brine shrimp at PetsMart and I may yet change to that. But for now, I’ll see the “sea monkey” hatching project through and see how it goes. I expect I’ll have hatched brine shrimp by tomorrow so I will try some of that instead of the liquid feeds and see what happens.

Just as an aside, I found a page on About.com that mentions their top picks for “small fry” food.

While these are primarily small fry as in baby fish, they all contain the multitude of nutrients need, and in an accessible, easily digested liquid form for young aquatic creatures. So I’m not too concerned.

Frankly, even though the Kent Marine ZooPlex is supposed to be for larval invertebrates, I have to say I’m more happy with the “dispersal” ability of Wardley’s Small Fry food. Wardley’s is a milky liquid that spreads completely and uniformly through the tank, so the most food and nutrients are available to the most number of critters.

The Kent’s on the other hand, is like ground up bits of brine shrimp in a pink liquid. The instructions say a teaspoon per 50 gallons, and since I’ve only got a 10 gallon tank, I am giving 1/4 tsp of the stuff. However it seems like precious little food, that probably isn’t getting to anywhere near the number of baby fiddlers that are hungry and needing to eat. So at least so far, I’m not that impressed with the Kent Marine ZooPlex and will stick primarily with Wardley’s. From there it’s live or frozen brine shrimp.

I raised the salinity of the aquarium yesterday to 1.017 from 1.012. I’d be happy to get to 1.020, which is close enough to a marine environment. I’ll leave it there for a couple weeks then, and gauge the appropriate time to lower it back down to brackish. I want to match that to the development of the more advanced crab forms from the initial larval stages.

As to the adult crabs – they’re doing fine in the main tank. Admiral Byrd, flush with mating success these days, never stops waving his claw. In fact, yesterday, I no sooner put Scarlett O’Hara back in the main tank, and he was right there saying “hi.” She hid behind the water filter to eat…though not too hidden, he actually lay backwards and slightly upside down on the water heater near her, and waved his claw at her upside down. Talk about “never give up.”

Anyway, so far, so good. We’ll see how this progresses over the next few days. It would be nice to keep many alive to actually make it to adult crab stage. Stay tuned!

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The Post – New Fiddler Babies

March 29, 2008

I was amazed to see babies born before Monday. Monday was 2 weeks to the best of my knowledge. So she delivered a couple of days earlier than I expected.

Anyway, yesterday started with me doing a 30% water change as nitrite levels in the tank since Scarlett has been in there, have been hovering between 0.5 – 1.0 ppm. I kept the water filter running to give the water the best chance of staying nitrite free and letting the nitrogen cycle mature.

This evening though, I noticed that Scarlett was very agitated. She kept running back and forth in the tank, climbing up onto the air bubbler and waving her claws in front of her as if trying to spread something in the water. There did not appear to be anything in front of her though. I noticed that the center of the egg mass seemed to be swelling. Given that, I went ahead and shut off the water filter.

For the next hour or two, Scarlett O’Hara kept moving around, seeming very uncomfortable. Around 8:30 p.m. I looked over at the tank and noticed she was sitting quietly in the front of the tank eating. She seemed “slimmer.” Looking closer, I realized, she no longer had the egg mass. So I missed the delivery again. However, a quick look around the tank and I could seen thousands of tiny little dots swimming around.

I fed them a small amount of Small Fry and ZooPlex. I wondered if this will go okay since I couldn’t get the nitrites to zero before they were born.

This morning I got up and looked at the tank. It was a white cloud. I thought, “Oh God, the water quality got worse with all the babies in there and the nitrites are probably through the roof.” I looked at the ammonia monitor and it is in the safe zone. I shined a light into the white murk and could see thousands of babies swimming around. So they’re still alive and ?healthy.

Wondering why the tank is so cloudy, I decided to recheck water parameters:

pH 8.0 – good; alkalinity 300, hardness >300, chlorine 0 – all great results, AND the REAL KICKER OF ALL: NITRITES AND NITRATES ZERO!!!! Puzzled, I repeated the nitrites test using a tube test instead of the dipstick. Again – nitrites are ZERO!!

So water quality is actually BETTER??? I looked in the tank and saw all the babies flitting around and MANY on the calcium sand at the bottom. That’s when the light bulb went off in my head. The water cloudiness is “white” like the bottom sand….could it be cloudy because thousands of little tiny guys are bouncing around against the sand at the bottom, eating whatever’s in it (since it’s ground up from live coral…possibly some microscopic food bits there?), and eating it for calcium for their molting?

If they were out in the ocean they’d have “bottom stuff” to dig around in so maybe this is a good thing? Though it certainly makes it harder to see them. For whatever reason, baby fiddlers seem to like to “head for the bottom” – at least some of them. That happened last time with many burrowing into the gravel and dying. So I will see how this calcium sand thing goes. I am PLEASED though that the water quality is so good.

For today – I need to go feed them again and I will need to start raising the salinity to ocean level. If that IS what should happen, they should survive. If not, well, we’ll find out. One step at a time.

The Post – Admiral Byrd is Peeking & New Aquarium Products

March 12, 2008

Some Fiddler Updates – New Product Technical Details and Romance

1) Preparations, Take 2, for the Fiddler Crab Nursery Tank:

I came home from PetsMart yesterday armed with calcium sand to replace the gravel in the nursery aquarium. That project will commence later today. The sand is actually something called Seachem Meridian Tidal Marine Substrate. It’s basically calcium carbonate precipitated from ocean waters by coral. It will stabilize the calcium and alkalinity levels in the water, and keep the pH from getting too low. Its porous structure and size supposedly are good for the growth of denitrifying bacteria. We shall see.

At the very least, it’s a dual purpose as I can also use this sand for the bottom of the land hermit crab cage I just bought. The land hermit crab project will be ramping up soon.

I also picked up some liquid food that should work fine for the larvae. I’d mentioned a product called JBL Nobilfluid that a gentleman from Finland used to raise his crab larvae. However the Nobilfluid is made in Germany and appears to be available in Finland, Germany, England, Italy and the UK, but I couldn’t tell if it was available here in the US. I could get it from a UK website but between the exchange rate and the shipping, I expect the cost is prohibitive. A JBL representative answered my email yesterday and said their product is not available in the US yet.

I found this new product at PetsMart called Kent Marine ZooPlex. The problem I had with the fiddler babies was trying to find liquid plankton to feed them. My mistake was getting live liquid phytoplankton, which made the tank toxic and killed them. I realized larval crabs need zooplankton, which is animal plankton = roughly translated: MEAT. Phytoplankton, being plant based, is the wrong plankton. Larval crabs are carnivores, not vegetarians. Anyway, Kent Marine ZooPlex is “concentrated aquacultured Marine Zooplankton” and is geared toward invertebrates including larvae. The bottle notes it can be used as a brine shrimp replacement. So this sounds like it might be just the thing for liquid feeding of newborn larval crabs who are too small to chase live brine shrimp around.

I will still need to get the dried brine shrimp eggs to hatch when I know I have a pregnant female ready to shed her eggs. The brine shrimp hatchery project will come a bit later.

2) How to raise the alkalinity of the water for the brackish tank without raising the pH?

The dilemma I have when using Instant Ocean to make up the brackish tank water for the adult crabs, is that I have to use it at about half strength. That way I get a salinity of about 1.010 instead of 1.020-1.024. The trouble is, that makes the alkalinity way too low meaning there’s not enough calcium in the water for the crabs when they molt.

I’ve tried adding Seachem’s Marine Buffer, to raise the alkalinity and it’s very successful, but it also raises the pH way up to 8.3. That’s fine for a marine tank, but for the brackish tank, the fiddler crabs seem to like the pH closer to 7.8-8.0 I have a constant battle trying to get the salinity low enough, the alkalinity high enough and the pH “just right” somewhere between a freshwater tank and a marine tank. When I use the Marine Buffer I have to then add something to lower to pH.

I was hoping to find something that would raise the alkalinity, but not the pH when I use Instant Ocean to make up the brackish water. Yesterday I came across Seachem’s Reef Calcium. The website description reads:

Reef Calcium™ is a concentrated (50,000 mg/L) bioavailable polygluconate complexed calcium intended to maintain calcium in the reef aquarium without altering pH.”

I am going to try the Reef Calcium product and see if that solves the problem. I will let you know.

3) Romance: a humorous update for a Wednesday:

Ever since his success with Scarlett O’Hara, Admiral Byrd has been out there claw-waving up a storm. Melanie Hamilton spends just about all her time inside the live rock. Yesterday afternoon is the first time I’ve seen her out of it in weeks. I think she took to hiding out in the rock when Scarlett O’Hara was living in the nursery tank. With Scarlett temporarily gone, Melanie was the total focus for Admiral Byrd. I don’t think she liked that.

Anyway, after giving birth, Scarlett O’Hara has been eating almost non-stop. I think she finally slowed up a bit yesterday, but she’s still pretty ravenous. In fact yesterday, I dropped a shrimp pellet in the tank and Scarlett scrambled up and caught the thing in mid-drop. It never even touched down on the gravel. And she’s pretty good. No fumbling and bobbling the shrimp pellet. She spotted it, she jumped, clutched it to her chest and landed on her feet, eating the pellet before she landed. She could probably earn a spot as an outfielder for the Red Sox.

Unlike Melanie Hamilton, Scarlett hasn’t been too concerned one way or another with Admiral Byrd’s where-abouts. She doesn’t run from him, or toward him. She just eats. Still, I don’t think she’s averse to his presence as she’s spent a fair bit of time in his lair, the fake rock cave, while he walks around waving his claw. I have to wonder if he realizes she’s sitting in his house?

Last night I turned off the tank lights, shut off all the house lights and went upstairs to bed. A little later I had to come downstairs for something and walked by the tank. Even in the dark, I could see Admiral Byrd standing there on his gravel hill, waving his claw. Total darkness, but the crab is still out there trying to get the attention of the ladies of the tank. What dedication.

He is also very funny in his pursuit of Scarlett O’Hara. He climbs to the top of the live rock, to wave his claw of course. Yesterday while claw-waving, he caught sight of Scarlett down on the gravel next to the live rock. He stopped waving, tip-toed to the edge of the rock, peeked over the edge at her to see which way she was going, then, like a teenage boy in love, scrambled down the rock and followed her around all the while waving his claw.

So watch out Scarlett, Admiral Byrd is peeking.

The Post – A Fiddler Update – Water Issues and Decreased Numbers

March 7, 2008

I am not sure that things in the nursery tank are going well. A sudden reversal in fortunes over the last day or so. Very decreased numbers of babies. In fact, this morning, it’s hard to tell if there are any left. The water got cloudy, like an algae bloom, and the nitrites spiked high and even a touch of chlorine showed on the dipstick, odd since I use distilled water. So the chlorine is coming from tank conditions, not the water I used. Some thoughts:

I am not sure if the decrease in numbers is:

1) Normal? They cannibalize each other.
2) High nitrites?
3) Touch of chlorine?
4) Wrong food?
5) Too much or not enough food?
6) Salinity? Are the science articles wrong and should I have left it brackish?

Water quality:

It started out that the water would get cloudy for a little while after I put food in the tank. Then it would return to being clear. Now, however, it’s cloudy all the time. I replaced 1 gallon of water last night (still “marine” at 1.019), and I added buffer to raise alkalinity for them to have enough calcium to molt. I also added Prime to get rid of chlorine and decrease nitrites. I succeeded with raising the alkalinity, and eliminating the chlorine. Nitrates are still in the “okay” zone, but nitrites didn’t drop.

This morning the tank is still cloudy. I will recheck parameters in a little while, and probably replace another gallon of water. I hate to do that because if there are babies left, I am most likely pouring some of them down the drain with water I tank from the tank. I do pull the water from the side of the tank where the babies did not hang out much, but still. Nothing to be done there though. a.m.

It occurred to me this morning that maybe the phytoplankton was either a bad idea or I just gave too much. The phytoplankton is alive. I noticed the water I drew off last night had a greenish tint. That means the phytoplankton, which is PLANT plankton, and alive, may be blossoming, in fact, maybe it’s a phytoplankton bloom in the tank. Given it’s not the open ocean, but a closed environment, the bloom, while successful in generating more food for the babies, maybe too much of a good thing in an aquarium. If too much growth, is it raising the nitrites and killing off the babies? I am wondering if I should have left the food at “Small Fry” and maybe the ground up krill and not added the phytoplankton.

I will also put a sample of the water under my “precision” microscope later to see if in fact the water is jammed with plant cells.

I will update on the results of water change, microscope viewing, and repeated parameters later, as well as whether it looks like there’s any babies left.

Live and learn. As my husband says, “Next time”….I think there’s always things we can do better. AND, once this experiment is over, we’re going to leave that spare tank up and running empty so it can settle out with a matured nitrogen cycle. Stay tuned for updates.

The Post – Extra! News on Preparing the Fiddler Crab Nursery

February 23, 2008

So you’re like me and you’ve got a pregnant female fiddler crab. Now what?

Well, we just came home from Petsmart with a second 10-gallon tank, lid, light, and pump/filter assembly so I can set up a saltwater aquarium in which to put the babies. Maybe I’m crazy for trying to see if I can raise them …?then sell them? but the challenge of motherhood calls. My husband, a geek of a different nature, respects this need in me to see if I can do this. He quietly acknowledged that he would “understand and be willing to fund” a second tank for the “kids.”

The dilemma now is did I wait too long to get it set up and get the “nitrogen cycle” started before she releases the babies? I can take a patch of the filter gauze from my current tank, which is loaded with nitrogen-fixing bacteria, and put it in the new filter to “seed it” with bacteria.

Tomorrow I’m going to Fish Pros in Raleigh NC to get another good-sized chunk of live rock. Between the filter seeding and the live rock, that should get the water parameters in the safe zone and the bacteria up and running quickly. Also the live rock will provide calcium for the many molts the little ones will need to go through.

What I was not sure though was how I would be able to “catch” the babies since I won’t know when she releases them and I won’t know if they’ll be too small to see once she does. Also, should I make the second tank a regular “salt-water” tank to represent the “open ocean” like most fiddler babies go to, or make it brackish like what they’ll end up in? This last question got further complicated by the information I found on the blog below that indicates I should isolate mom before she releases the young. So I have much to ponder tonight while I get this up and running.

I did a search for info on pregnant fiddler crabs and come up with The “Dear Blue Lobster” blog entry” from July 25, 2007. The Dear Blue Lobster site claims to have been answering “your crustacean questions since 2002.” This entry is from someone who is concerned that her fiddlers make have “hooked up” and now what should she do? She is freaking out at the prospect of a 100,000 babies in her tank.

The gentleman who runs the blog gave good technical advice on taking care of the pregnant mom, saving the larval babies, raising them, and even indicated how much/lb. you can sell fiddler crabs for over the internet. The crustacean guru also gave the following emotional advice:

“So what do you do if your female is indeed pregnant? Comfort her. Her man has kicked her out and will no offer care for her children — in fact, he may try to eat them! ….Good luck to you and your Fiddlers. Motherhood is a special blessing indeed.”

Since it is well past July 2007….I wonder how the mom (human) and the mom (fiddler crab) made out with their situation? For myself, we shall see. I am off to set up the tank. I guess I’ll set it up brackish and isolate mom before she “delivers.” I have also emailed Dear Blue Lobster for help on what I should do. I’ll keep you posted on his reply.

I recommend the blog. The crustacean guru is Christopher Chimwish. His site description is as follows:

Christopher Chimwich received his MMN in 2000, specializing in decapod behavior. He is currently surveying benthic decapod populations in the Indian Ocean for his doctoral thesis. Chris answers questions about crustaceans, covering everything from DNA mutation in African crayfish to Fiddler crab sign language.

By the way, if you want to be a real geek, apparently the term for my fiddler crab when they have the brownish eggs attached to their abdomen is being “in berry.” So.

If you want to know what he has to say about fiddler crab sign language, click here.

The Post – Scarlett O’Hara and her molted ghost

January 31, 2008

fiddler-crabs-242.jpgfiddler-crabs-252.jpgfiddler-crabs-254.jpgfiddler-crabs-287.jpg

Well, I’ve been promising pictures of the fiddler family members so let’s start with Scarlett O’Hara and her recent molt.

The first picture shows her just after she molted, climbing down the side of the water filter. I love how they can have their eyestalks going in two directions as they move about. If you look closely, the right eyestalk is vertical, while the left one is scanning in a horizontal direction. Off to the right in the picture, her whitish “ghost” sits, discarded. With the water currents waving the legs and claws back and forth, the discarded shell looked eerily alive.

The second one shows her nestled safely under the water filter and behind her old self (fuzzy part in front), where she rested for some time. It is not unusual for newly molted crabs to hide. Their new shells are soft at this point and they feel vulnerable. So they hide to give themselves protection as their new shell hardens.

The third picture though a bit dark, gives you a close-up view of the ghost version. You can see the empty leg, claw and eyestalk casings. I will add that the “ghost of Scarlett O’Hara” no longer exists. Admiral Byrd ate it. Perhaps he is getting ready to molt. Crabs often eat discarded shells to reclaim the calcium the shells contain.

Last picture shows Scarlett O’Hara when she finally emerged from under the water filter. Still a bit tentative, she sought shelter under an overhang on the Live Rock.

These were all from Saturday, the 26th. Today she was back to her old self, running around the tank and eating. Maybe I can get a lighter picture of her now that she’s out and about. I need to work on “lighting” issues for these, but still, not bad considering no flash and long exposure times.

Soon to come, Admiral Byrd and Melanie Hamilton!!!

The Post – EXTRA! Scarlett O’Hara molted!

January 26, 2008

This warrants a quick extra post today….NOW I understand why Scarlett O’Hara spent almost 10 days in the Live Rock – she must have been preparing to molt. I don’t know if she stayed in the Live Rock cavity because she felt vulnerable, or because being near it probably gave her extra calcium (it leaches out of the rock into the water), and she needed extra calcium for the new shell she was creating under her old one.

I assumed she must have molted inside the rock, though given her size it had to be tight quarters. I also wondered why if she was back to her old self, she spent the last 24 hours hiding under the water filter and not eating. Neither thing is like her at all. She generally does not hide, and she ALWAYS eats.

Anyway, I came in carrying groceries and my husband said to me “You are going to want to see this.” We both moved quietly and carefully to the side of the tank. There, underneath the filter sat TWO perfect Scarlett O’Haras – the real one with her new shell, and the “ghost” one…a perfect shell of her old body just sitting there underneath her.

SO!! We have successfully seen one of our crab children molt. How exciting!

The Post – Scarlet O’Hara Lives! And How I Came to Love Fiddler Crabs

January 25, 2008

After almost 10 days without a sighting, FINALLY yesterday afternoon, I spotted Scarlet O’Hara. I wasn’t sure at first if she was just a corpse, dangling upside down inside the Live Rock with her eyestalk hanging down, but shining the flashlight into the rock’s cavity at 5 minute intervals, I was able to determine that a) she actually had moved her position, and b) on the second and third times, she reacted to the light beam and flinched. This latter point was important because it meant the movement was deliberate, not the result of her just being bobbed around in the cavity by the water’s movement.

Relieved to know she wasn’t dead, I went ahead and did the water change. (More on that below) Then last evening, Scarlett O’Hara emerged from the Live Rock Cavity, and slowly started moving around. She resembled a patient just released from the hospital – someone tentative in her steps and tired after her ordeal.

Okay. Right about now, I’m sure anyone reading this is wondering what the hell I am talking about. Let me back up to the beginning and give you the Readers’ Digest version of events. I am contemplating setting up a separate blog – Crab logs – to capture all the events since the beginning of this endeavor, for those purists who only want the “lab notebook stuff.”

As I’ve mentioned I am writing a mid-grade novel called Under the Pier. At least that’s the “working title.” The protagonist of the “under” the pier side is a hermit crab. While I had no trouble pinning down facts about the creatures in that world, those chapters lacked “heart.” They read more like a nature guide. My husband read the first few animal chapters and noted that frankly, he didn’t care about the creatures. That’s a death knell for any book, whether the characters are human or animal. The whole point of reading a story is to feel what the characters feel, live through the story struggle with them, and stay along for the ride because… you CARE about them. If my husband didn’t care about them at chapter 2, I had a problem. So, back to research.

It occurred to me that I just hadn’t captured what it felt like to be an undersea creature. Since I can’t live underwater, an aquarium is the next best thing. I couldn’t have a marine hermit crab like the one in my story as a pet because that meant setting up a salt water tank, something reputed to be very difficult. PetsMart had something called “freshwater crabs.” A freshwater aquarium meant cheap, at least cheaper than a saltwater one, and easier. I’d had aquariums as a kid. I figured I could set up a small tank very inexpensively, get a couple crabs, and voila….live research that would teach me how to emotionally bond with something I normally eat in garlic butter. As I’ll describe below, “cheap” didn’t take place, but emotional bonding did. My husband noted that I bought myself $4 worth of fiddler crabs, and $100 worth of support gear. 🙂 In reality, it’s been way more than that by now, but . . . more about that later.

Anyway, I bought two males, not through any particular strategy. Those 2 just happened to wander into the net the teenage employee swished through the store’s tank. I rushed home with my new “pets” and all my gear and rapidly set up the tank. Normally, when you set up an aquarium, they recommend getting everything established before bringing home your fish. However in this case, I figured why bother setting it up ahead of time when the saleslady made it sound like all these guys needed was some water and a bubbling air tube. Again, more later.

The larger male immediately ran around his new tank, explored every aspect, took command of the gravel hill (they need an area where they can be out in the air for up to 50% of the time), and showed no fear. Given his apparent “explorer” mentality, we named him after the South Pole explorer, Admiral Byrd. The smaller male immediately bolted under the water filter and stayed there for 2 or 3 days. Even when he came out, he skulked around in the background. My husband noted that he acted like the Peter Lorre character in the movie, the Maltese Falcon, so we named him Peter Lorre.

I’m going to skip over the travails of learning I should have set up the aquarium first before buying the crabs, the fact the people had us buy the wrong food (how are bottom-dwelling crabs supposed to eat krill shrimp that only float on the water’s surface and don’t sink?), and the many things that made me realize these crabs really do need more than a bubbling air tube if they were to live longer than the 2 weeks PetsMart’s written guarantee said they would.

As it turned out, Peter Lorre made it about 3 weeks before he died. I think his poor little body just wasn’t up to the stresses of toxic nitrite and nitrate levels, not to mention the fluctuating salinity levels (see below). By the time I learned about Live Rock and how it speeds up the nitrogen cycle in the tank and makes things healthy and non-toxic, Peter Lorre just stopped walking one day, tumbled off the live rock, and dropped headfirst to the bottom of the tank, dead. I was heartbroken…he was the quiet timid one, and I did like him. My husband couldn’t understand how I could care about him given that I ordinarily do not hesitate to go to a seafood restaurant and consume his cousins with great enthusiasm. Doing a twist on that line from the Godfather movie about things not being personal, but business, I said to my husband, “This is personal, not lunch.” When things get personal, you go to Google for answers.

Now, for any aquarium geeks – a couple things. Live Rock, as mentioned above, is rock taken from a tropical coral area, and contains microscopic sea life and bacteria. By adding a1 pound chunk of cured Live Rock (ie has been allowed to sit in a salt water tank and age and no longer smells like a salt marsh) to the tank, it essentially seeded the tank with nitrogen-fixing bacteria. They speed up the establishment of the Nitrogen cycle. That’s where toxic ammonia and nitrites generated by the biologic wastes in the water, are converted to nitrates. Eventually the levels of ammonia, nitrites and nitrates drop to zero. The Live Rock also has the benefit of leeching calcium into the water. This comes in handy for keeping things like pH and calcium at stable levels. Crabs need high calcium for molting. Anyway, once I added Live Rock to the tank, the toxic conditions subsided rapidly. But not in time for Peter Lorre.

I also learned that the crabs I bought were “red-jointed fiddler crabs,” otherwise known as Uca minax. Sometimes PetsMart sells the yellow-clawed ones, Uca pugnax, or mud fiddler crabs, but I definitely got the red ones. While these crabs can survive in freshwater, it apparently shortens their lifespan considerably. I read somewhere that they can live a year or more if kept at the right salinity. I figured salinity meant “marine.” After all, if they weren’t freshwater crabs, then they were salt water crabs. I went out and bought aquarium salt and made it up to the regular marine aquarium specifications, a minimum specific gravity of 1.020. I eagerly added the water to the tank figuring my guys would react with glee. Instead, Peter Lorre went into a daze and foamed bubbles out of his shell. Admiral Byrd bolted out of the water like I’d just added sulfuric acid and literally tried to climb the walls of the tank to get out. I didn’t understand it. I’d followed the directions and they “should” have liked the water, but obviously they didn’t. Even fiddler crabs deserve not to be in pain so I added some plain water to dilute things. They settled down.

In hunting around some more on Google, I discovered that these crabs are in reality, brackish water critters. That is that “estuary” type environment where the rivers meet the sea. The water is neither freshwater nor saltwater. Brackish water has a much lower level of salinity. Further, I found a study of fiddler crabs in the rivers of Delaware that really illuminated the problem. Uca minax – the red-jointed guys – prefers water with a specific gravity of around 1.008 – 1.018. Any higher than that and the LD50 (the time it takes for 50% of the population to die) is 2- 3 weeks. Same if you put them in freshwater.

Interestingly, according to the study, the yellow-clawed guys LIKE the higher salinity. If I’d had Uca pugnax crabs instead of Uca minax, they would have loved the higher salinity water. But my guys hated it. They needed….brackish. That’s how it goes with me. I start out to have a simple freshwater tank, then accept I must make it marine, only to find out I have to actually set up a brackish tank…something by the way, very few people do probably because there’s no books on the subject. In any event it’s been quite the adventure, and I sure have learned a lot, becoming a bit of an expert now on maintaining a good brackish water environment, a source of pride for me. However, this should explain now, my husband’s comment about $4 worth of fiddler crabs, and a $100 worth of support gear. It goes without saying I needed a gauge to monitor specific gravity not to mention water conditioner, solutions to decrease the ammonia until the Live Rock bacteria kicked in, and test strips to check the water…a lot. 🙂

Anyway, end of geek moment and back to the story:

Well, now that Peter Lorre was dead, Admiral Byrd was beside himself. He sat in his little cave tunnel near Peter Lorre’s dead body and just twitched. I thought he’d eat Peter Lorre given that they are scavengers, but apparently fiddler crabs don’t eat their friends. I removed Peter Lorre and gave him a proper pet burial in our front yard, next to the gerbils, hamsters, and pet rat buried out there. Then I set out to buy Admiral Byrd more friends.

I found this amazing aquarium store on the outside of Raleigh, NC – Fish Pros – Fishprosnc.com SALT WATER TANKS and ALL KINDS OF GEAR and PEOPLE WHO KNOW WHAT THEY’RE DOING!!!!. In fact some of their staff are marine science students or professors at NC State University nearby. In any event, I left there with not just ONE more friend for Admiral Byrd, but three. And this time, there would be WOMEN!

I figured keep the numbers even, so I bought 2 females and one more male. The man at the store noted that having the females would produce some neat “claw-waving” mating behavior in the males – the crab equivalent of “Hey baby, check me out!” Also, since females weren’t territorial, it was possible to have more crabs in the tank without having fights. Needless to say, Admiral Byrd perked right up when he saw he had friends, and when he realized there were ladies, well, he hasn’t stopped waving his claw since.

In any event, the male struck my husband as the “Rhett Butler” type, so, the new guy became Rhett Butler. That meant following the Gone With the Wind motif for the ladies names. The larger female demonstrated an overbearing, fearless, almost aggressive streak. She became Scarlett O’Hara. The more timid, fragile female, is Melanie Hamilton.

Again, for whatever reason, we lost one of the crabs – Rhett Butler lay dead in the back of the tank. No outward evidence of “foul play” ie – Admiral Byrd killing him off for territory or women. Again, another pet burial in the front yard. However, since then, the remaining three crabs have done fine. Yes, the women get fed up with Admiral Byrd chasing them around. And Yes, Melanie Hamilton got tired of Scarlett O’Hara stepping on her to get to the food pellets. Melanie Hamilton spends most of her time living INSIDE of the Live Rock chunk. She does peek out the front or side entrances long enough to grab a food pellet and pull it inside, and every now and then she will climb out and wander around, but she’s very skittish and races back in the rock at the slightest provocation.

My Scarlett O’Hara concern started about 10 days ago. She enlarged the front entrance to the Live Rock, ie, pulled out a bunch of gravel and tunneled under it to get inside it with Melanie Hamilton. For a few days I could see them both crammed inside the Live Rock if I shined a flashlight into one of the rock’s openings. But for the last 10 days I could not find a trace of her. At first I figured she went in there to molt. Molting takes a few hours. So, I figured give her another day or so to rest and she’d be back out. No dice. No matter how often I shined the light into the rock, all I could see was Melanie Hamilton. By yesterday I’d decided Scarlett must have died and I needed to pull the rock out of the tank, if only to remove her dead body for burial.

However, just before I did that, I shined the light into the Live Rock and lo, that’s when I saw Scarlett O’Hara. She was clinging to the roof of the cavity, and I could see her eyestalks hanging down. Since she emerged from the rock, all is back to normal. Scarlett O’Hara and Admiral Byrd run the tank and wander constantly, seeking food. Melanie Hamilton peeks out of her cave and pretty much stays out of sight. As odd as it sounds – I am so HAPPY!!! I really felt bad at the thought she died. Seeing everybody doing their usual thing, it’s like “aaahhh, back to normal.”

Oh – one last geek moment, a moment of pride for me. I did a 33% water replacement in the aquarium yesterday – almost double the 18 % change the time Admiral Byrd freaked out about the salinity, and more than the recommended 25%. I didn’t have much choice given that the water really needed changing. I added the water and held my breath, keeping a close eye on Admiral Byrd. Apparently, this time I did it right. The tank water was at a 1.010 specific gravity, and so was the new water I was adding. Not only that, but the other parameters were great : pH 8.0, total hardness (GH) >300 ppm, total alkalinity (KH) 300 ppm, chlorine and nitrite 0, and nitrates “okay” at 20 ppm. (I’ve been using the Jungle Laboratories brand Quick Dip 6 Tests in One strips). And Admiral Byrd? He just kept right on eating through the whole thing. Never once climbed the walls…he never even left the water. SUCCESS!!!

Now I’m saving my allowance to buy …. two land hermit crabs!!!! Stay tuned soon for their adventures.

And stay tuned…working on getting pictures of Admiral Byrd, Scarlett O’Hara, and Melanie Hamilton…if she ever comes out of her cave!