Chromis Tail Bitten Off!

[yzfdave]

So, I have a 72 gallon fish tank with: 1 yellow tang, 1 blue hippo tang, 2 clown fish, 1 Koran angel, 1 Flame angel, 2 Cardinals, 2 Chromis, and 1 sand sifting goby. I've had the tank for over a year with literally no problems. However, this evening I noticed that one of the chromis' tails has been bitten off. The 2 chromis, while I've heard can be aggressive are actually very calm and compatible with all the other tank mates. They were the first 2 original fish to be placed in the tank. Any ideas as to what may have happened? Like if the tail could have been bitten by one of the other fish, and if so any suggestions or thoughts for which fish it could have been??

And since he has very little left of his back tail, will he survive if left in the tank on his own? Or is this a case for a mercy killing? (eeeks, I hope not.) We have him quarantined in a critter cage in the tank right now to protect him from further attacks.

Thanks in advance!

[BangkokMatt]

Possibly a night time crab attack!. I would wait to see if it heals. It should be ok providing it is still eating and can swim / balance reasonably well.

[Gwynhidwy]

I would also suspect a crab or possibly a shrimp. Have you been feeding less recently? Any other changes or additions, particularly rocks?

[Gwynhidwy]

I also agree that you are probably best off leaving the fish in the tank if he is still swimming and eating normally. Watch for signs of a bacterial infection, if you see any I would remove the fish to a QT and treat there. I would not euthanize the fish in this situation.

[Mentat]

<a href=showthread.php?s=&postid=14643067#post14643067 target=_blank>Originally posted</a> by yzfdave
...And since he has very little left of his back tail, will he survive if left in the tank on his own...
If only the fin part was damaged the tail should grow back in a couple weeks. However, if tail base (caudal peduncle) was damaged, it probably won't. Either way fish should make it, unless wound gets infected.

A picture would help making a determination IRT tail regrowth potential. Recommend stay on top of water parameters until healed.

[yzfdave]

We don't have any large crabs. We have only 2 incredibly small, baby-like crabs. I doubt they could attack anything, let alone a large damsel. Before we quarantined him he wasn't eating much, and was staying up close to the top of the surface in one spot. It looks like he has definitely been having trouble swimming. And his other chromis buddy used to come up to him and kinda bumped him, like "what's up buddy, let's go!" I thought maybe he's dying and the other fish are bitting him off because they sense he's in distress?? any other thoughts?

[Dooly]

when I had a few chromis in my 120, 2 of them got their tails bitten off and they were bleeding, couldn't really swim and died overnight...

found out that my solar fairy wrasse likes to bite small fishes tails..