Breeding of the batik crab--Metasesarma obesum

[lucasjiang]

Recently, i managed to get a female batik crab. A few days later, it was holding eggs. Now 3 weeks later, this wednesday morning, the eggs were finally released. I transferred the crablings to a saltwater set-up with a air pump bubbling gently. They are fed on phytoplex phytoplankton (i was trying to find for liquizell, but to no avail). Sadly, the population has been reduced greatly, probably due to overfeeding, and i am reducing my feeding now. Here are some pics of my set up and the crablings

Setup:

in the day:



at night




Crablings:
whole mass of them:


close-up:






Thanks for viewing

[blue33]

WOW.... that's alot...

[johannes]

do they eat infusoria?

maybe if they do, in the future, you can prepare a tank of infusoria in advance to feed the crabllings.

[lucasjiang]

hmm, they are saltwater , whereas infusoria is freshwater, so i think if i put infusoria inside ,they will just die and rot, which isnt very good. A better option is to culture my own phytoplankton, but i didnt manage to culture them fast enough.

[johannes]

oh ok, i overlooked that point...

anyway congrats...

how about BBS then? too big? or they need plant material thus you mentioned phytoplankton.

[lucasjiang]

i think you know what is euglenia, it is the micro-organism that makes up green water. Daphnia feeds on these euglenia. The crab larva are basically saltwater daphnia, about the same size, and they feed on the saltwater form of greenwater ,called phytoplankton. i think anything the size of daphnia wouldnt be able to eat BBS.

[johannes]

you meant Euglena sp., oh ok, so you do have the culture. that will make things easier but still fry/crabling death is inevitable...
i am not experienced in crabs but how about installing a small sponge filter in the crabling tank, is it useful or redundant?

please update the crabling when they are bigger..

good luck bro!

[lucasjiang]

i seriously dont know about this, very few people have successfully managed to raise these crab larvae, so there is very little information on the net. I will continue to update (that is if they survive). thank you.

[blue33]

this might help, click >here< , they have others also, you can check them out.

[lucasjiang]

Hi adrian,

When i went around sourcing for a food for the larvae, i saw this product too. However, i chose phytoplex as this one contains all sorts of plankton, of which most of them are not suitable for feeding my larvae, whereas phytoplex is purely phytoplankton, which is suitable for my larvae.

[dkk08]

Congrats bro Lucas and that's really alot

[lucasjiang]

thanks desmond

sadly, the population has been decimated, very high mortality rate.

[dkk08]

Well Lucas, at least you can be proud to be one of the few to breed them till this stage

That's quite an acheivement for someone your age

[aquarius]

With the high motality rate the ammonia level will go up. Maintain good water quality... Usually fish farms when rearing lavae stage they don't change water (don't knw for how long) but due to your high motality rate you may have to change water but it's very risky cos at this stage of their development, they are very very fragal. Btw maybe next time you put in a very much bigger tank so that there is a bigger vol of water which makes the water more "stable".

[hwchoy]

Lucas, a very good job

[guqin]

Rearing of crab larvae is tedious and will really test your patience and dedication. This is what I used to do. Get several transparent fishing tackle boxes like this (http://campingnfishing.com/index.php..._image&pID=306) and put three to four larvae into each compartment. Ensure you have plenty of clean and aged seawater to make one or two water changes to each compartment.

Food is the difficult part. If you have a laboratory dedicated to rearing larvae, there will usually be algae culture to feed the larvae. If not, you will have to hatch brine shrimp nauplii everyday until the larvae is large enough to take bigger day-old or bigger nauplii.

You will need to feed the larvae perhaps two to three times a day. Squirt enough nauplii for the larvae in each compartment (about 10 per larvae) and remove all uneaten nauplii after an hour. You can also make a water change at the same time when removing the nauplii.

Keep all the rearing boxes in a cool place. Some light source will be good but not so strong as to cook them. It is not really essential. After a few days, the larvae will start moulting. You will need to remove the moult. At the same time, you will have to thin out the larvae because the bigger ones will eat the smaller ones in the same compartment. In the end, you might have only one larvae in each compartment.

After enough moults, the larvae will finally reach a stage called the megalopa (big eyes) stage. This is the final larval stage and after one more moult, the crab will become a full-fledged juvenile crab.

This method is tedious and time consuming. Successful rate is possible 50% or lower. The good thing is you do not need elaborate equipment like filters or lighting systems to culture algae. Hope this helps.

[hwchoy]

thanx unker guqin for the guidance. now lucas we want to see daily pix

[guqin]

Could you post images of the mother crab so that we can confirm the identification?

[hwchoy]

I thought you need the body?

[guqin]

Don't scare people leh. One step at a time.