What crab is this?

leo12345 · Mar 31, 2023

Got a few of these in with my live rock and the biggest one I saw was a little over half an inch.

blaxsun · Mar 31, 2023

These look like gorilla crabs. You don't want them (or at least relegate to the sump).

leo12345 · Mar 31, 2023

blaxsun said:
These look like gorilla crabs. You don't want them (or at least relegate to the sump).

Are they bad at this size?

blaxsun · Mar 31, 2023

leo12345 said:
Are they bad at this size?

I think it's more a question that they can grow quickly and become a problem in short order.

AydenLincoln · Mar 31, 2023

Bad gorilla crab! Evict him!

leo12345 · Mar 31, 2023

blaxsun said:
I think it's more a question that they can grow quickly and become a problem in short order.

What size do they become bad, and is it one google it says they are poisonous. Is this true?

blaxsun · Mar 31, 2023

leo12345 said:
What size do they become bad, and is it one google it says they are poisonous. Is this true?

They're bad from the outset, and will eat all inverts and even small fish as they grow. Yes, they are poisonous - but this is more with consumption, ie: don't try to cook and eat these crabs.

Bucs20fan · Mar 31, 2023

They are the paramount omnivore as far as hitch hikers go. They will gladly eat any fish they can catch, hermits, snails and dont shy away from corals if they are hungry.

ILikeFish! · Apr 1, 2023

Bucs20fan said:
They are the paramount omnivore as far as hitch hikers go. They will gladly eat any fish they can catch, hermits, snails and dont shy away from corals if they are hungry.

Crap. I also got a few of these. are they hard to catch? how big do they get, and how big of a fish can they eat?

blaxsun · Apr 1, 2023

ILikeFish! said:
Crap. I also got a few of these. are they hard to catch? how big do they get, and how big of a fish can they eat?

They can be hard to trap, but do a few searches for crab trap and you'll find some helpful suggestions. How big? Probably fist size eventually, so whatever they can catch...

ILikeFish! · Apr 1, 2023

blaxsun said:
They can be hard to trap, but do a few searches for crab trap and you'll find some helpful suggestions. How big? Probably fist size eventually, so whatever they can catch...

My smallest fish is two inches how big would it need to be to eat it?

blaxsun · Apr 1, 2023

ILikeFish! said:
My smallest fish is two inches how big would it need to be to eat it?

This is directly proportional to how slow the fish is and how hungry/motivated the crab is. But I imagine a 1.5-2" crab might take a swipe at it.

kjkszpj9 · Apr 1, 2023

almost looks like some kind of sally light foot crab but its claws are way to big to be that.

Bucs20fan · Apr 1, 2023

Its not always about how close in size the crab is to the fish. Its about opportunity. The crab can hide all day, and it takes one wrong move from a fish that is small enough to be immobilized by a good pinch. Even these small crabs pack a punch with their claws. if they could pinch you, trust me you would feel it. Ask anyone whos been pinched by a large emerald crab, its not the greatest experience trust me. If the crab gets a good pinch in, it will bring the fish close, pinch with the other claw, and then eat it alive. It sounds gruesome, but thats how they do it.

ILikeFish! · Apr 1, 2023

Bucs20fan said:
It’s not always about how close in size the crab is to the fish. It’s about opportunity. The crab can hide all day, and it takes one wrong move from a fish that is small enough to be immobilized by a good pinch. Even these small crabs pack a punch with their claws. if they could pinch you, trust me you would feel it. Ask anyone whos been pinched by a large emerald crab, it’s not the greatest experience trust me. If the crab gets a good pinch in, it will bring the fish close, pinch with the other claw, and then eat it alive. It sounds gruesome, but thats how they do it.

So as long as the fish only swims in the water Column and doesn’t lay down it be fine?

KING KONG · Apr 2, 2023

ILikeFish! said:
So as long as the fish only swims in the water Column and doesn’t lay down it be fine?

As stated,In short they attack the fish when they sleep and lights r off. Believe me they r a terror. I hv cought 15 till now. U may see some fishes can kill them but none will eat them. Your small fishes will be in a great danger. U can see these crabs hiding in rock holes. If u see your fishes suddenly disappearing, that means crab has eaten your fish. U may also see some 'moults'. Sometimes, U can see them in night with red flashlight.

If u see one gorilla crab u may also hv more. U can identify these crabs with their 'sharp' claws. Crabs which feeds on algae, their claws r not sharp, they r kind of flat claws.

ILikeFish! · Apr 3, 2023

KING KONG said:
As stated,In short they attack the fish when they sleep and lights r off. Believe me they r a terror. I hv cought 15 till now. U may see some fishes can kill them but none will eat them. Your small fishes will be in a great danger. U can see these crabs hiding in rock holes. If u see your fishes suddenly disappearing, that means crab has eaten your fish. U may also see some 'moults'. Sometimes, U can see them in night with red flashlight.

If u see one gorilla crab u may also hv more. U can identify these crabs with their 'sharp' claws. Crabs which feeds on algae, their claws r not sharp, they r kind of flat claws.

What fish will kill gorilla crabs?

KING KONG · Apr 4, 2023

ILikeFish! said:
What fish will kill gorilla crabs?

It's depend on individual. Aggressive fishes sometimes kill gorilla but you may don't want that kind of fish in your tank. My cinnamon clown used to kill gorilla crabs but it also killed many fishes so best way is to try to remove those crabs.

Also fish only kills the crab. They will never consume gorilla crabs. May be coz of the toxin it contains. Gorilla crabs can also harm your invertebrates, if u hv any. They'll also multiply faster. Triggers r known to eat these but will also harm your invertebrates