Unidentified Crab having Babies

[Frigideus]

I posted another thread trying to identify some crabs I had in my tank, and while it is still unclear to me what they are (Ive gotten quite a few different answers atp), I discovered a third one, and this one is carrying eggs. I don't have any lfs I can drop these off at, and I don't know if they will play nice with the sea hare that lives in my sump. Does anyone have any idea what I can do with the pair? She was pretty far back in the rocks so the picture is awful. Any advice is appreciated.

 

[strich]

I'm no crab expert, but I do believe its very hard to see crab eggs reach any kind of success in a tank without a lot of effort on your part - They get eaten or sucked up in filters and skimmers. So I imagine you don't really have to worry about it.

Again, not an expert, but looks a bit like a gorilla crab and if so isn't safe around most things including the hare.

 

[CheifReeferNB]

These are Red Mithrax crabs. You can tell by the claw shape. Same family as emeralds, mostly reef safe unless they get very hungry and they snack on corals. As far as the eggs go, it would be very unlikely to see them successfully raised in a reef tank.

 

[kevgib67]

Definitely red mithrax crab, I have about half a dozen in my tank with about the same number of emerald crabs. Mine have caused no problems and spend the day munching on algae all day. They are prolific eaters of bubble algae so if any get introduced to your tank there won’t be any problems. I’ve had emeralds in my tank for about four years, never have they reproduced. I think their larval stage gets eaten and/or sucked up on the filtration.

 

[keagan]

The rounded tips on the claws show that the crab has a diet of mainly algae and biofilm. "Bad" crabs like gorilla crabs have pointed claws for catching and dismembering prey. Gorilla in particular have black tips on said claws.

If you want to OP you could raise the larval stage in a reactor setup if you can culture enough food to raise them. It's not exactly easy but it's fun to try.

 

[Frigideus]

I have several mating pairs in my tank, these crabs, a pair of peppermints, and my porcelains have also exploded in population (there's 20 or 30 just chilling in the tank probably) but at the very least I rarely need to actually feed the fish since they have gotten so used to eating live goods and don't like the frozen mysis much anymore anyways.

I think the main problem is that my cleanup crew is a bit too prolific, especially my quoyi who cleaned up the entirety of the tank in about two days and is now without food because of how quickly it ate all the algae. So now they just like to go around and harass corals. I offer them seaweed but they don't seem to pick it over coral. They don't really seem like they 'eat' coral either, they just kinda taste test it and when they decide they dont like it theyll just dump the frag somewhere.

I have actually agreed with what people are saying about the crabs on this forum so I will post the third one here as well and see if anyone can get a read.

People have called this one a mithrax, a spider crab, a gorilla, etc. and I can't get a good read on this one. Has pointier claws but is extremely docile as far as temperament goes. Hangs out with my shrimp and porcelains virtually all day. Main issue is, again, they just don't go for nori sheets and like to redecorate using my frags.

Any advice is appreciated. I really like these crabs but just have no idea what to do with them.

Pictures:

 

[kevgib67]

I have several mating pairs in my tank, these crabs, a pair of peppermints, and my porcelains have also exploded in population (there's 20 or 30 just chilling in the tank probably) but at the very least I rarely need to actually feed the fish since they have gotten so used to eating live goods and don't like the frozen mysis much anymore anyways.

I think the main problem is that my cleanup crew is a bit too prolific, especially my quoyi who cleaned up the entirety of the tank in about two days and is now without food because of how quickly it ate all the algae. So now they just like to go around and harass corals. I offer them seaweed but they don't seem to pick it over coral. They don't really seem like they 'eat' coral either, they just kinda taste test it and when they decide they dont like it theyll just dump the frag somewhere.

I have actually agreed with what people are saying about the crabs on this forum so I will post the third one here as well and see if anyone can get a read.

People have called this one a mithrax, a spider crab, a gorilla, etc. and I can't get a good read on this one. Has pointier claws but is extremely docile as far as temperament goes. Hangs out with my shrimp and porcelains virtually all day. Main issue is, again, they just don't go for nori sheets and like to redecorate using my frags.

Any advice is appreciated. I really like these crabs but just have no idea what to do with them.

Pictures:

I don’t see pointed claws, I see the same cup claws of the mithrax. Time to call in the expert, @ISpeakForTheSeas

 

[Aqua Ultraviolet]

Looks like a small Mithrax-type or similar reef hitchhiker crab. The eggs will hatch into tiny larvae that almost never survive in a closed tank. These crabs can turn opportunistic as they grow and may stress or bother a sea hare, so if you can trap or remove the pair that is the safest move. Otherwise just watch them close.

 

[BloopFish]

i agree its a red mithrax crab and that the zoea are unlikely to survive in a reef tank