My paradise fish has lost his mind.

[MyCatsDrool]

He went psychotic last night. He has been living happily in a 55 gallon community aquarium for quite some time, a year or more, when last night, he finally lost it. He puffed himself up huge and attacked everything in site. It was like watching the Bruce Lee of the aquarium world crossed with the Incredible Hulk. He killed one of my viel-tail angelfish, and took a good sized chunk out of another's fin. He killed a molly in one blow/bite/ He attacked a pearl gouramy and took out one of her feelers.
He even tried to mess with a 7 inch plecostumus, but quicky discovered that was a bad idea. He tore up plants even!

He has been moved to his own tank now this morning, a 10 gallon I set up in a hurry. He is in a bag in there right now, acclimating, and he is attacking the bag.

EDIT*** I just released him into the 10 gallon and he is looking at me like he might kill me in my sleep. I am worried.

[triazole]

breeding season? how big is he? any bubble nests around?

I had a cory cat that did the same thing. To this day Im not sure what made it go postal on the other fish. It didnt care how big the other fish were, it would relentlesly chase them, even turning a larger clown loach pale grey. It would even chase it's own species, attacking them. I tried isolating the fish, thinking maybe it had a parasite in it's brain causing this aggressive behavior. I even went as far as trying to treat it for a week in a q-tank. But when I returned it to the community tank, it took up where it left off. I ended up having to take it to the lfs. I felt bad, but there was nothing else I could think of to do at the time.

[MyCatsDrool]

He is about 4 inches, tip to tail. He's a big boy. No bubble nests, but I do think he wants to breed. I am going to call the local fish shoppes today and see if anyone has a sheila for him.

[onah]

just fyi, even if he just wants to breed the behavior wont change after he has blown his load, typically he will stay pretty aggressive, i had one i had to give up to a 5g home of his own, i want to put him back in a larger tank eventually, but after reading this and other posts fear that it wont be anytime soon, mine is about 3.5" he grew about 3/4" well i had him, he is such a cool looking fish, i loved watching him sprall out his fins! Dam shame he had to go as a matter a fact i think i am gonna go cry for a bit now

[onah]

just fyi, even if he just wants to breed the behavior wont change after he has blown his load, typically he will stay pretty aggressive, i had one i had to give up to a 5g home of his own, i want to put him back in a larger tank eventually, but after reading this and other posts fear that it wont be anytime soon, mine is about 3.5" he grew about 3/4" well i had him, he is such a cool looking fish, i loved watching him sprall out his fins! Dam shame he had to go as a matter a fact i think i am gonna go cry for a bit now

oh one other thing, if the sheila u find dosent want to breed he may just put a beat down on her till she gives it up, and they dont always survive that, my advice get a bigger girl if possible(if not atleast the same size) so she can hold her ground for a bit, in case she aint in the mood(IMO).

[JeffreyL]

Don't give up all hope yet! Had the same thing happen with an angel. Got to be about 3.5 inches & turned aggresive, culminating in an after hours fight with a red tailed shark. The shark was dead & the angel recovered in solitary. Finally after 3 or 4 months I tried putting half a dozen cherry barbs in with him ........ and all is fine!!!! A little shooing of the barbs when they get hyper, and he will not share food, of course. But really the tank is peaceful. I am not going to try another RTS, though.

What I have been told repeatedly is a complete change of environment & tank mates will often work. But it is still a gamble, more so if the aggresion is hormone related. Good Luck!!!!