[Fishhead Junkie]

what predator in my tank could possibly be killing my fish so quickly? i am losing fish left and right for no reason. i just came home with a straitius tang about 2 hours ago, i let him float for over an hour, placed him in the tank, messed around placing some new coral, and when i went looking for him i find him in the back hiding by the heater. at first i thought he was just scared, then i notice his rear area near his tail looked funny...i stuck my hand in there and his tail end is all chewed up beyond repair....i mean seriously. i can only think of a few things in the tank that might do that sorta damage that quick..

decorator crab
emerald crabs

i have yet to see the decorator get aggressive with any of the fish, the emerald crabs will snap at a fish every now and then just to let them know they are there. i am totally shocked. this was almost a 2in fish, gone in an hour...i have a clown, chromis, hawkfish, and gobies much smaller that are swimming around without a problem. any ideas?????

steve

[jvharding]

What are the tank inhabitants? Is there live rock and how much. Tank Size is? What are your water parameters? How long has tank been Established?

[Fishhead Junkie]

its a 29gallon bio-cube, i set it up 1 1/2 to 2 months ago, started it with about 40lbs of aquacultured live rock, all pre-mixed sea water(no red sea salt), ph is good, ammonia is good, started doing weekly water changes a week ago(changing out about 2.2 gallons), i am probably a couple fish over my limit but i have a clown fish, a hawkfish, 2 chromis, a orange spotted goby, a firefish, a decorator crab, a brittle star, the usual hermit crabs, emerald crabs, snails and a bunch of different corals. a brittle star couldnt of eaten a big tang in an hour, i cant see the tang sitting there while a crab munched on him. i could swear the decorator crab was in plain site most of the time. it was really weird, it was all chewed up on the underside of its tail(severely). i just flushed it. the heater couldnt burn chew marks into it. oh yeah..there is also a horseshoe crab in there and i know it wasnt him cuz he only comes out like 2 times a day and swims around like a retard. i am having the worst luck with this tank. i cant stop looking at it everytime i sit on the couch, i just want the fish to surive more than an hour.

steve

[nammy]

Sure its not a Mantis?

[benesh10]

It could only be a crab. and not one of the 2 you said you have. I had a mystery guy grow in my tank eventually after months of what your going through I caught a glimpse it was black with 1 huge claw 1 small. it was in a 60lb. piece of great live rock. I had to take the whole rock out. but the problem was resolved. Try taking your bigger pieces of rock out and see if the problem is resolved. THe crab I had must have been so small and just grown and grown. since my rock was years old. finaly just got big enough to eat fish.