Pet Information > ASK Experts > Pet Fish > Pond Water Gardening > Agressive fish

Agressive fish

25 10:00:27

Question
Hello again,
I wrote to you the other day about moving my fantail (approx 2" long - not counting the tail)from the 5 gal. aquarium to the 275 gal. pond which had 7 common goldfish in it (each goldfish is about 3" long or so - not counting tails). Well he is now in the pond.

The goldfish have been merciless in chasing him around and pestering him. The goldfish all look the same so I can't tell if it's the same goldfish doing the chasing or if they are taking turns. The goldfish get right under him as if they have their nose up his butt and just chase and chase after him. Sometimes it's just one goldfish and sometimes 2 or 3 are doing the chasing. Right now the fantail is hiding as there are several small ledges, nooks and crannies for hiding, but the goldfish seem to try to go after him even in the hiding places.

Is this much agression normal and how long would you advise waiting before I take him out of the pond - assuming I should take him out at all. If I have to remove him, I don't want to wait too long, but I would like to give them enough time to get used to each other. On the other hand, I don't want a tortured fish. I've been able to inspect him when he's close to the surface, and I don't see any nipped fins or sores on his body.

In the past, the goldfish have have always been very active, would chase each other around, change directions, chase each other again, etc., but I never noticed any overt agression from any of them toward each other. I went on your website but couldn't find anything on fish agression and bullying although I've read that they are territorial and can bully each other just like all animals.

I'd appreciate your input and knowing if you think this will all pass or should he be removed from the pond. Have a good safe Labor Day weekend and thank you again.

Answer
Regular sorts of goldfish are more active and can pester fancy goldfish to a dangerous level.  Your 3" goldfish are a bit young to be interested in breeding but the chasing and ramming her rear are typical spawning moves.  A 2" fantail is not very likely to carry eggs (if she's a she even).  Goldfish will also chase new fish because they're new and interesting.  If the fantail seems to be getting hurt, I would remove her for a while.  They may get used to each other but it may take a week during which time she could get hurt so it's a delicate balance.  With 2 and 3" goldfish, I wouldn't think they would really harm each other so I might wait and see and only remove the fantail if you notice injuries or the chasing seems to never end.  Sorry I couldn't give you a definitive answer.  Good luck!