Crab during cycling tank

[al404]

Hi

I'm about 3 weeks of cycling the tank
Today I found this crab. Not sure if is dead or changed his shell

Never seen it before.

Do you think is dead?
Would it be a good or bad guy for small fish like gobidon okinawae?

 

[Mr. Bill]

IMOPE, all true crabs are opportunistic feeders. It's not a question of IF they will kill tankmates, it's a matter of when. That said, your crab is lying on it's back, so either that's a molt, or he's dead.

 

[Dkuhlmann]

Yes a bad crab for a reef tank usually with that type of claws. Pick it up and open the shell from the back, see if it's empty shell or full of crab meat. LOL It's more than likely a molt and you will need to make a trap to catch it. I've got a new rule, no crabs of any kind in my DT with the exception of scarlet hermits.

 

[al404]

I picked up but is too small to understand if is a shell
today i saw a crab claws from a rock but as soon as i got closer it disappear
are crab shy? do they walk around in the dark?

would it be dangerous for fish or for what else?

 

[Dkuhlmann]

Many of the bad crabs will eat fish, corals and your cuc. Nothing good about any crab IMO and IME. It sounds like you found a molt. Yes they are skittish and right after they molt they hide for a few days for their shell to harden. The crab is very soft when first molted.

 

[stingeragent]

Outside of hermits, most of the crabs are skittish.

 

[Mr. Bill]

Outside of hermits, most of the crabs are skittish.

Yep, and nocturnal.

 

[whosurcaddie]

You want to get a glass jar and put a piece of shrimp in it. Lean it up against the rock in a vertical position with the rim touching the rock. The crab will go in but cant get out. This is one of the easier pest problems to solve.