My crab's eggs have hatched...

[Vaideen]

Today I noticed that: a) My crab, which has been carrying eggs for a couple weeks, is now missing its eggs, and b) there's a ton of tiny black specks swimming around in the water. How should I care for the crab larvae? There are no fish in the tank yet (I'm gonna add a few small fish later), just the mother crab and a couple of crayfish that I just found out to be pistol shrimp.

[Subsea]

Difficult to keep, I would think.  

 

Either establish an invert culture by growing phyto then feeding to micro invert like rotifers.  If you live near a salt water estuary, you might introduce planktonic  food in that manner.. 

[Oldsalt01]

Odds are against them surviving, unfortunately. Larval stages of most crustaceans generally won't survive the filters of your tank, and as Subsea noted without plankton the food chain just isn't there for them. U may luck out, and a few may survive. It's a crap shoot.

[Vaideen]

Oh, that sucks. Oh well, maybe I'll just leave them for my fish to eat. At the moment, the tank is only run on a single airstone, though I am getting a Sicce Voyager Nano in a few days.

[Subsea]

I should caution you on keeping crabs, of any type,  in a reef tank.  While I do use Emerald Crabs, often to my chagrin.  I often see Emerald Crabs pull mussel flesh from Flower Anemone.  Hermit Crabs are on my “do not allow” list as well.  Snails whose populations reproduce  to food supply are on the “good boy” list.  There are differrent functions to be performed by the CUC.  

 

I feel confident to say that Crabs will prey on members in your CUC.

[Vaideen]

I didn't know crabs would do that. My CUC consists of the crab, two pistol shrimps and a couple snails. The pistol shrimps always scare away the crab, but I'm not so sure about if the crab will eat the snails 😕

[Subsea]

Can you clearly see the tips of crab claws?  If both tips are flat, then it normally eats algae.  Emerald Crabs have two flat tips, yet they can easily be a problem.

[jambon]

If you have your mind set on trying to raise any... I would put a sponge over the intake of your filter to stop them from being sucked in. 

[Vaideen]

Yeh the edges of the crab's claws are flat, it doesn't seem to be the aggressive, hunting kind of crab anyways.

 

I'm not really interested in raising the crab larvae, but a large number of them dying might cause an ammonia spike, so better hope they either grow up quickly or get eaten quickly.

[Rob22]

Highly doubtful on the ammonia spike. Not that anyone would do this, but if you think about it if you were to capture all of them and mash them together they are no bigger at this stage than a small lump of crab poop. If your crab can poop multiple times a day, these perishing shouldn’t affect water quality. They won’t likely all die at the exact same time and start to decompose either. 

 

If you realy like crabs crabs I would suggest a porcelain crab. They have claws but don’t really use them. They are actually predominately filter feeders and wave tiny fans in front of their face. Awesome little crabs but kind of shy depending on your livestock. 

[Subsea]

29 minutes ago, Rob22 said:

Highly doubtful on the ammonia spike. Not that anyone would do this, but if you think about it if you were to capture all of them and mash them together they are no bigger at this stage than a small lump of crab poop. If your crab can poop multiple times a day, these perishing shouldn’t affect water quality. They won’t likely all die at the exact same time and start to decompose either. 

 

If you realy like crabs crabs I would suggest a porcelain crab. They have claws but don’t really use them. They are actually predominately filter feeders and wave tiny fans in front of their face. Awesome little crabs but kind of shy depending on your livestock. 

While a Pom Pom Crab would not be a problem, it would not contribute as a member of CUC.  Also, tanks needs to be mature to support this filter feeder.

[Rob22]

Not sure if it was a typo or you misread me, but I’m speaking of a porcelain crab, not a Pom Pom crab. They will also scavenge or eat bits of mysis. You can supplement their food source. How much they will do as a member of a clean up crew would be debatable, but they are reef safe and will not attack snails or shrimp. 

[Vaideen]

Porcelain crabs look pretty cute, might get one or two for myself haha.

 

Pom poms look cool too but as stated, they need a mature tank.