Just wanted to post this to the forum to try to gain a better understanding of the fish that I keep. I have a 3" rainbow shark that has lived happily with 2 young angelfish in a 26 gall bowfront for about 9 monthes. I knew that the fish would grow.and need a bigger tank, but they all seemed happy and peaceful. Well, I got a new 75 gall for christmas and decided to put the angels, 4 gourami and the rainbow shark in the new tank as a permanent home.
There is plenty of space and hiding places, plants... but immediatly upon being introduced to the new tank, the rainbow shark started chasing and ramming ALL the other fishnin the tank! Even the angels that he had lived with happily for so long. I gave him overnight to see if he would settle down, but in the morning, he was still at it. Fish have frayed fins and missing scales...hiding. So I resolved the situation by putting the shark into my cichlid tank. I was sure they would rip him up, but no one seems to notice him at all.
Has anyone seen behaviour like this before? I've been in the hobby for many years and I've never seen a fish change so quickly and totaly from 100% peaceful into an absolute terror.
The new tank is cycled and stable, I can't imagine anything about the tank that would upset the shark so drasticaly.
Any input or personal experiences would be greatly appreciated as I have no idea what happened to turn my lovable, happy shark into a violent psychopath!