Posts Tagged ‘tail’

The Gift – A Fiddler Crab Extra From a Fellow Crab Enthusiast

March 18, 2008

One of our readers sent in some information the other day about her attempts to raise fiddler crab larvae. That comment was in response to my blog post entitled:

The Fiddler Babies are Dead But We’ll Start Over and Prove HorseyhannahWrong.

Yesterday Laurie has this update that she posted on one of my other blog posts: “Extra! News on Preparing the Fiddler Crab Nursery.”

She has such good info, and generously wants to share it with all, so I include it here for all to see.

I especially loved what she said toward the end of her comment, that maybe if all of us who have knowledge on the subject of fiddler crabs pool our info, we can prove that you CAN too raise fiddler babies without the hundreds and thousands of dollars of equipment that Horseyhannah (on the Animal Planet forum) says you need.

So here is Laurie’s information, her gift to all fiddler enthusiasts out there, updating us on her progress and also listing the many things she’s done to make this work. Thank’s Laurie! And to anyone else who might have more info for myself or Laurie, please do send your comments. They are welcome!

Fiddler crab lovers of the world, unite!!! 🙂

Comment:
Laurie’s Fiddler Crab fry–March 17th, 2008, Day 7 and still going…

Just an update. They were released on March 10th and true to the (artist!?) breeder of the mangrove crabs www.aquahoito.info/sesarma/index.html on March 15th, day 5, I had a little more than half die off. In the last 2 days no more have died, tho.
Today I was able to get supplies for them, including a salinity meter ($7.00) and some test strips for nitrate/nitrite etc. and Kent’s PhytoPlex (not live) for more food. As I didn’t have proper food for them I did the newborn fish fry trick of feeding them hard boiled egg yolk. About 1/2 a matchstick head’s worth smashed fine in some water and dispersed with the fry, twice a day. That was too much, no doubt, but I’m new at crabs and they did ok…

I tested my water (2 gallon hex w/no filtration, slight bubbling from airstone) and nitrates were 0, nitrites were alright-“caution” .5 ppm, salt is .015ppm, hardness 300 (ideal). I’m finding it’s cheaper to do water changes in a small fry tank than buy a whole salt water filtration system. 2 tbsp Ocean Reef salt/quart, 1 qt every couple days. The little squirts only have to get to 2 or 3 months old before they’re little crabs, by the looks of Mr. Mangrove Crab’s work, so that’s not much salt used over time versus the complexities of a nitrogen cycle filtration system. Now that I have test strips I’ll know how often that should be.

Again, shutting off the bubbler, wiping the bottom to free the slime that’s growing there (I don’t think I’m getting it all, so if it’s food it’s still present somewhat), then fluffing it to one side and siphoning it up w/airline tubing seems to clean the nitrite creating stuff pretty well. Shining a light in one corner for them to aggregate near keeps most of them out of the way, and I shine it again in the gunk glass I siphoned into to get the ones I accidently sucked up back into the tank.

One interesting note is that after the “D-Day” day 5 die off the herd that is left swims less and congregates on the bottom on the side facing the window. Their movement is now more like a thousand little frogs hopping around in the herd at the bottom of the tank. Some still swim, but majority is doing the new movement. I can see a bit of their tail now, but no major growth change.
Possible theories: 1.) they molted on day 5 and many didn’t make it through. 2.)Nitrites killed them at this stage and they haven’t molted yet. 3.) Maybe everyone’s dies at day 5 because they have 5 days of food stored in them or because when they molt the new contact with water conditions isn’t right for them…
Interesting to note that my water isn’t the right ppm for salt, but half have survived… I thought I saw somewhere it should be ocean water (1.020-1.024, and somewhere else 1.010. hmm. Wish I had more tanks to test all 3 salinities.

My hope is that with more postings from folks that are having success we can all help each other out to solve this mystery and not make silly statements like it taking hundreds of thousands of dollars to get the right water conditions for this. heh heh that one still makes me chuckle. I bet it’s possible.

Folks could try their filtration systems in their nursery tanks with a big ball of fiber-fill around the intake (intake on LOW!) with super fine cloth over that. That makes the drag into the intake almost nothing. You’ll see if the babies are being pulled onto it, it’s too strong still… but I still am having great water results with one gallon of water in a two gallon tank.
Best… Laurie

The Gift – A Fiddler Crab Extra!! Meet the Babies!

March 2, 2008

fiddler-crab-under-100x-magnification.jpg

Okay. You’re wondering what in God’s name this thing is. Well, it’s one of the crab babies, at least my rough sketch rendition of one. (If  you want to see real photos of the zoeae and later larval stages of fiddler crabs, click here ).

It’s the best I can do. I’m spoiled because I am used to working in labs with good equipment.

In the lab I would have put an aliquot of liquid from the aquarium in a test tube, spun it down in the centrifuge, poured off the supernatant, and made a slide out of the sediment, which would be concentrated crab larvae, instead of chasing one unlucky soul all around the microscope slide trying to catch him long enough to see him.

I would have had nice stains to chose from to make the larvae show up better. Today I had McCormick’s yellow food coloring from Harris Teeter.

I would have had a nice Zeiss microscope with oil immersion lenses and fine optics. Instead, I have a Milben kids’ microscope, circa 1965, in a wooden case, with an EverReady 5 volt flashlight shining in the mirror to light the stage. (And if you want a kick, click here to see a similar setup to my microscope and wooden case. It even has the dissecting kit tool indentations in the styrafoam. I had those dissecting tools a long time ago. It says something when you search Google for Milben microscope and it’s listed under “antique sites.”)

I would have had a nice Zeiss microscope with a camera attached to photograph what I saw. Instead, I had to sketch it. I don’t have one of those neat electronic tablets to draw with. All I had is the “pencil” tool on my son’s Photoshop program that I barely know how to use.

So, I know, stop whining. I’m not in the lab anymore. Given all this, I still managed to catch one crab baby, watch him through my very “SUB-OPTIMAL” microscope, in food coloring stain, and draw you a WAY suboptimal sketch.

But still, what the sketch shows is the head part on the right, with two little “?claws” moving back and forth rapidly. It stretches out with the tail on the left. We could even see “material” moving through the crab from the head, out the tail. Yes, out the tail. My husband caught that one. So I guess we can assume the crab baby has been eating the food I served. 🙂

In any event, minus all the fancy equipment, it’s the best I can give you, but still it’s something. I should note that this was a 100x magnification.

We have noted that Days 1 and 2 there was a fair reduction in numbers of larvae and my husband noted the blackened area that looked like a mass murder in one corner of the tank deep down in the gravel where many babies perished. Still, there are LOTS of babies swimming in the tank AND they are bigger than yesterday. If you hold a magnifying glass up to the tank, you can see tiny tails. So some are thriving after all.

If many many thrive, at least the guys at Fish Pros said they’d be happy to buy some from me for cash or store credit. That would be great. I’m always in need of new supplies. 🙂

Salinity is almost “ocean” at 1.017. Should reach 1.020 later today.

Anyway, now you’ve “sort of” met the babies.

….about that centrifuge – it occurred to me I could take a small, capped plastic tube and tie a rope around it and spin it around my head. Then I thought, maybe even better – tape the tube to the inside of my washing machine and run it on the spin cycle. But leave it to my engineer husband: find a way to attached two capped tubes on a rod opposite each other, connect them to a power drill, and turn the drill on….THAT’S the best RPMs for the money. 🙂