black ghost knife fish

Question
I have had a black ghost knife fish for about 6 months now. It is in a 55 gallon tank with only 5 other small fish. It's tail has always curled just a little, but lately it has gotten a lot worse. It's tail now makes a curly cue,and no other part of it's body seem to be growing as fast as it's tail.Is this normal? If not, is there anything I can do?

Answer
Hi Milea,
I have never heard of this, so I have tried to research this for you. So far all  I have been able to find is that when they are searching for prey they will bend their tails.  I don't know if this is what your fish is attempting to do but since he is in the same tank as smaller fish, maybe he is attempting to hunt the other fish with his electrical abilities. I do know that they are capable of eating other small fish. Since he is one of the types of fish that use electircal impulses to help with hunting for prey maybe that is what he is doing when his tail is bent.
The only other possibility could be that at some time his tail area was injured and it could be causing it to grow abnormally or sometimes fish will have slight deformities and be healthy otherwise. Since he is most likely still growing, it may start to straighten out as he matures. As far as you being able to do anything about it, I think only providing good quality water and food would be all you could do. Since he doesn't really appear to be sick, it might be just a matter of waiting to see if in time it will become more straight.
Hope this helps,
Karen