fish disapearing...

[discotu]

so in the past couple weeks I've had the following fish mysteriously disapear...1 diadem anthias, 2 chromis, and a flame hawk. I checked the normal places (overflow, sump) but nothing. I did find the half eaten remains of the hawk floating along the bottom so I figured it much be some sort of predation...but based on the fish I have that is unlikely the case. Here's my stock list in my 225g.

powder blue tang
blue hippo tang
purple tang
yellow tang
mandarin goby
blue neon goby
arabian pseudochromis
2 green chromis
3 diadem anthias
flame angel
pair of tonga flame wrasses
royal gramma
red stripe anthias
black perc

I did noticed that around the same time a black brittle star moved to a new rock...I am wondering if he could be the culprit? I am sure if a small fish swam into it's hole, he could wedge or trap the fish. In terms of size, my best guess is that brittle star is at LEAST 5" in diameter. any other thoughts??

 

[cl2ysta1]

mantis shrimp hitchhiker. They generally come in small, and dont bother anything than the get larger and you notice fish missing

 

[Charlie's Angel]

Do you have any rock crabs of Sally light foots? I had a rock crab come in as a hitchhiker and it took out a large racoon butterfly before I figured out what was going on. Finally got him out after a tank switch. I also think that large sally's can be predators on smaller fish if they are hungry enough.

 

[JHemdal]

Green brittle stars (Ophiarachna incrassata) can predate fish at night. They perch up on their legs, and when a small fish moves underneath them, they drop down and capture them. Your's isn't the same species, but it could possibly behave the same way.
I've suspected a large "bobbit worm" Eunice sp. to be picking off some Anthias in a 1300 gallon reef. The worm is at least 3 feet long.
The key to determing what happens to "missing fish" in a reef is to first know for certain that the fish didn't jump out, or that it died due to some issue and got scavenged, rather than predated upon. The hawkfish for example could have died from a disease and then got scavenged by other critters in the tank...

Jay

 

[Tech Diver]

Black brittle stars can be quite agressive if hungry. Keep yours well fed with meaty foods (like shrimp, scallops or squid) and it should leave the fish alone. I had one that was at least 12 inches across and when I did not feed it for a week I believe it ate my Brazilian Gramma.

 

[discotu]

I've rulled out jumping/carpet surfing since I've got the thank covered. I also pulled out the brittle star and it was much smaller than i thought...i would be very surprised if it could handle a fish.

Don't mantis shrimp make clicking noises when they hammer? And don't they also feed on snails too? I've got tons of those small snails that come out at night...

I do have at least one black mithrax crab. His shell is probably about the size of a quarter. Could he be the one?

 

[techigirl78]

Have you looked at your tank at night? I have moonlights making it easier, but it is how I got my first glimpse at a crab hitchhiker that was in my tank.

I'd probably move the crab to the refugium if you can get it out. Are you sure it is a mithrax crab? I never had problem with green mithrax crabs, but you never know. After catching a black crab from my tank - I no longer have missing shrimp and fish: http://www.reefcentral.com/forums/showthread.php?s=&threadid=1106401&highlight=crab

 

[discotu]

Based on the pics from this website, it's either the xanthid shown on the 3rd row, or the mithrax shown on the 3rd row. One distiguishing sign is the shape and color of the claws. Time to build a trap...

http://home2.pacific.net.ph/~sweetyummy42/hitchcrabs.html