Aggression with goldfish?

[Sssea]

I'm curious to see if anyone else has experienced aggression with fancy goldfish.

I have a rather large 4-5inch brown oranda named Hans that doesn't seem to get along well with other fish. For over a year, he only had one tank mate who unfortunately fell very ill and had to be euthanized. This was several months ago and since then I've tried adding 2 other fish and he brutally attacked them both.

The first was about the same size and they instantly fought, it was terrifying. I even rearranged the tank and gave them a few days to see if the aggression would settle, but they were relentless. I passed it off as the new fish being unfriendly, so I returned him.

The second fish was much smaller and very passive. This seemed to go well for about a month or so. All I noticed was a few little scuffles at feeding time, Hans is incredibly fast (and chubby) and would eat most of the food before the other could get to it. One day I came home to the poor little fish almost torn to pieces and barely holding on, so I immediately removed it and took it back.

I've heard from my lfs that this is really unusual with goldfish. Any ideas on why it keeps happening or if there's any luck on finding him a friend?

 

[Sssea]

Oh no! I guess I'm the only one!!!

 

[jlk]

No, its not unusual. I am guessing Hans is a male & dominant one at that. I have one 'alpha' male that beats the poop out everyone else in the tank. Luckily, the two other males are larger than him & can hold their own but I do occasionally have to give him 'time outs' in either another tank or in a large pasta colander in the tank when he gets too rough.

You may have a difficult time finding him a 'friend'. My suggestion would be to look for another goldie bigger than Hans & heavily rearrange the tank before adding the new goldie & keep Hans in pasta colander while the new goldie explores the new environment. If the new goldie is a male, there may be fighting. If the new goldie is female, then you may see breeding behavior. Make sure the new goldie is bigger & an agile swimmer. Good luck!!

 

[Cichlid Kid]

I agree with jlk. I also have a large male oranda 14yrs old! His name is muscles and he also displays dominance year round whether it be in my 650gal pond out back or in the winter inside. His space is about 4sq. feet and all but a few female are aloud to enter, so when i intro new goldies i put muscles in a floating fishing net for a few days n this seems to break the ice a bit.