Posts Tagged ‘fresh water’

The Post – Odd Goings-On in the Fiddler Tank – Is Scarlett Acting Pregnant Again?

March 16, 2008

When I first I walked by the fiddler tank yesterday morning, I was sleepy and oblivious. Then I did a double-take. Sitting at the front of the tank was the discarded molted shell of somebody. On closer examination, and with my husband’s consultation too, we both agreed it was Melanie Hamilton’s discard. That means she is at the moment most likely to get pregnant if Admiral Byrd invites her in.

At the same time we noticed that Scarlett O’Hara was sitting on top of the water filter….again. The last time she did that, we noticed shortly afterward that she was pregnant.

Admiral Byrd of course, was marching up and down the tank, claw arm held high, and waving.

To continue – Scarlett O’Hara spent the entire day and evening yesterday, on top of the water filter. She is still there this morning. She has never done that before or since, except when she was pregnant. I know she is still alive because she is “blowing bubbles.” Crabs foam sometimes when they’re out of water, to moisten their gills.

Even when I freaked out Admiral Byrd yesterday, and scared Melanie Hamilton out of her live rock because I was cleaning the tank and accidentally bumped the live rock, Scarlett O’Hara didn’t leave the filter perch. She just moved down into the filter for a bit, then climbed back up. Admiral Byrd meanwhile kept trying to climb the heater power cord up to the top of the filter to be near her, but he couldn’t quite do it with that large claw.

Yesterday afternoon we noticed that Melanie Hamilton remained outside the live rock, sitting there on the gravel serenely watching Admiral Byrd flex his claw. Then she spent the rest of the afternoon and evening in his cave lair. This morning she was resting just outside his lair, picking algae off the rock. He was napping inside.

With any luck, we can try the larvae thing again somtime soon?

I am in the middle of re-establishing the nursery tank. I had emptied everything from the original set-up, cleaned out the tank, put down the one inch or so of the calcium-releasing sand, and added the water. Now I did forget to rinse the sand out, so the tank water was cloudy at first, but it has settle out by now. I’m not sure how one effectively rinses sand out anyway without half of it going down the drain. I will say the white sand really makes the inside of the tank bright when the light is on. If we get babies again, it should be much easier to see them in such a bright tank.

I couldn’t decide whether to make the 3 gallons of water I added marine or brackish. I guess I should start brackish because first we’ll have to move the mom, whichever one of them it is, from their tank, which is brackish into this one. I wouldn’t want to shock them. Right now the tank is on the “marine side” of brackish. I’ll adjust the salinity with a bit more water shortly.

The live rock is back in the tank hopefully doing its thing to establish the nitrogen cycle. Both the air filter AND the bubbler are running and so hopefullly the tank environment will establish itself as quickly as possible. Rather than replace the old water filter cartridge and lose whatever nitrogen-fixing bacteria that had started to thrive in it, I left everything in place and returned it to the tank.

An interesting about the old water in that tank. I tested it before I emptied it out just to see if the nitrite levels ever came down. They read zero, and the nitrates were in the “okay” zone. I guess once I stopped using the live phytoplankton and let the water filter run for a few days, that was what it needed. So the phytoplankton was most likely the culprit in the high nitrites. In any event, I dumped the old water and just started with fresh sea/brackish water all over again.

One thing – that Reef Calcium product that I’d hoped would raise the alkalinity but not raise the pH, when added to half strength Instant Ocean… maybe it didn’t raise the pH but it didn’t solve the problem of the pH being too high from the Instant Ocean even when I used that at half strength. So I still had to use a pH lowering solution and this morning it is about 8.0 vs 8.4 that it was yesterday. So that’s perfect . At least though, the Reef Calcium did raise the alkalinity.

I will keep you all posted on any news from the adult tank. Keeping good thoughts for a new crop of larvae babies. Stay tuned.

The Post – Baby Food Specifics, and Those Salinity Research Papers

March 2, 2008

First, I knew that Fish Pros in Raleigh NC would come through for me. I really wanted some kind of live plankton food for the babies as that’s what they would get in the ocean. I figured ground up TetraMin Tropical Flakes and ground up Tetra MiniKrill (freeze dried plankton) mixed with some Wardley’s Small Fry Liquid Food and distilled water would be as good as it gets, and I think it’s a pretty good mix. But I wasn’t sure I could grind the foods small enough for the pinpoint babies. Yesterday I took a ride to Fish Pros and lo, they had a bottle of DT’s Live Marine Phytoplankton – Premium Reef Blend. So this morning I mixed ground mini-krill in a 1/2 tsp of the phytoplankton and added a few drops of Small Fry in a little distilled water and put it in the tank. For other feedings, I’ll use ground up Tropical Flakes in the phytoplankton and Small Fry liquids. That should give enough of a mix of animal and plant material in their feed. The pet food link below for the Wardley’s Small Fry says that “live food” is best but for quick backup and unexpected births, the Wardley’s Small Fry is a good substitute. The DT’s phytoplankton is live.

For those truly geeky enough to want to know a bit about what’s in these foods:

DT’s Live Marine Phytoplankton: contains live Nannochloropsis oculata (yellow-green algae), Phaeodactylum tricornutum (diatoms or algae), Chlorella (green algae)

Wardley’s Small Fry: water, egg product, yeast extract, freeze-dried Calanoid Copepods (planktonic crustaceans that make up the biggest protein source in the ocean), and some vitamins and preservatives

TetraMin Tropical Flakes: fish meal, brown rice, shrimp meal, dried yeast, wheat, oat meal, fish oil, and a variety of vitamins and minerals.

Tetra MiniKrill – Freeze-dried Plankton: freeze-dried krill – Euphausia pacifica (shrimp-like invertebrates that are part of the zooplankton)

The Tropical Flakes can stay out at room temperature. Supposedly so can the Small Fry, though once I opened it, I am refrigerating it. The minikrill are in the freezer (yes, next to the loaves of bread but I don’t think I’ll mix them up), and the DT’s phytoplankton must be refrigerated. But again, I don’t think I’ll grab the phytoplankton when reaching for my husband’s bottle of blueberry juice. 🙂 So, that’s food.

The two articles for salinity in larval crabs:

Salinity Preferences in the Stage I Zoeae of Three Temperate Zone Fiddler Crabs, Genus Uca, Paul S. Capaldo, Department of Natural Sciences, Roger Williams College, Old Ferry Lane, Bristol, RI 02809; Estuaries Vol 16, No. 4, p. 784-788 December 1993

Dispersal and Recruitment of Fiddler Crab Larvae in the Delaware River Estuary, C.E. Epifanio, K.T. Little, P.M. Rowe, College of Marine Studies, University of Delaware, Lewes, Delaware 19958, Marine Ecology – Progress Series Vol. 43: 181-188, March 24, 1988

The first article mentions the three species of fiddler crabs in the study: Uca minax (red-jointed fiddler crabs, which is what I have), Uca pugnax and Uca pugilator, the latter two preferring high salinity areas. Uca minax prefers low salinity found higher up in estuaries, nearer to fresh water sources. The latter two are located in areas closer to the ocean, pugnax in salt marshes and tidal creek banks, and pugilator in the silt and silt-clay areas. The article notes that even though all three may inhibat the same salt marsh, because of their preferences for different salinities and locations, the competition for space and food between the three groups is greatly reduced.

So, today’s entry for all those who wanted geeky specifics on food and salinities. Enjoy!