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Will a crab take fish?

D

dearis

Experienced Reefer
G'day

I was searching over my live rock after the lights have gone out, and found a crab, red/pink with white markings about an inch round. Now the tank is cycling so its fishless, when stocked will the fish be a snack for the snail. We have also dicovered a smaller crab.

The amazing thing is we look over the rock everynight with a flashlight and have never spotted it before, live rock is amazing.

Regards Darren
 
M

Meloco14

Advanced Reefer
Is it smooth? Hard to say, but that coloration sounds like a type of porcelain/anemone crab or a crab that is symbiotic with SPS corals. I have had a crab living in my pocillopora for 2 years now that is mottled red/yellowish. Crabs are always iffy, but these types that I've mentioned are harmless. They filter feed, or eat symbiotically with their hosts. In general, the hairy crabs can become problems, and the small smooth crabs are ok. This is very general, though, so keep an eye on any crabs you may have. Some people will kill on sight any crabs just to be safe. Is the body of the crab an inch long, or does that measurement include the legs. If the body is an inch long that is pretty big, and may be a threat to certain tank inhabitants. In any case keep an eye on it and try to see what it feeds on at night.
 
M

Mihai

Advanced Reefer
If it has claws for grabbing food, then if it can catch a fish it will.
The fact that now is 1" is irrelevant - I grew a 3" crab from a 1/2" baby. At 2" it was eating everything in my fuge including a small goby and other crabs.

Regarding its size, I had my 3" Coral Banded Shrimp catch and hold tight a 3" mandarinfish without any effort (and a CBS has a much smaller claw and muscles than about any crab with the same size claw).

If I were you I'd either get rid of it, or isolate it before I put any fish.

M.
 
W

wade1

Advanced Reefer
Generally speaking, these crabs are total omnivores. They will eat what they can readily get. However, fish are not easily caught. Most of them will devour whole herds of snails (been there, seen that) before anything else, although they will certainly take on weak or injured fish in a hurry.

And yes, they will eat other crabs and shrimp and such as well.
 
F

fyrefysh

Advanced Reefer
dearis":113refvc said:
when stocked will the fish be a snack for the snail.
Click to expand...
:D

I don't think I've ever seen a snail eat a fish! :D

Anyways, if the crab is unidentified, then it's food source is also probably unidentified. I would probably quarantine it or give it to your LFS. Who knows, it may stay small and never give you any problems. On the other hand it could grow large and eat everything in the tank.
 
D

dearis

Experienced Reefer
Quote:
I don't think I've ever seen a snail eat a fish!

Cone snail, Conch, many others will take fish when they get large enough to.
Click to expand...

I do reckon i may have mistspelt snaol it should have read CRAB :oops:
 
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