Question on weird goldfish behavior.

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.


Aquarium Advice Addict
Jul 9, 2003
Frederick, Maryland
I've been noticing this weird behavior in goldfish on and off for a few months at work. Every once in a while after a new shipment I have to split up tanks of goldfish.

One fish gets completely banged up on. Its almost always two other fish who push their faces into the... "Butt" of the chased fish. They do this for hours, very much stressing the fish being chased.

I thought at first it was a territorial issue...but have never known goldfish to be territorial. Then thought maybe a mating thing...but I thought goldfish only bred in very cold water(water at work is on a chiller, temp steady at around 60F)? Or do I just have bullies? I think it really means something since the fish seem...quite literally, to have their face all over the butt of the other fish.

Any ideas?

Thanks guys! I'm totally lost on this one. :)
I can't say I've ever observed this behaviour in goldies. It might be a mating ritual though. I find it hard to believe the goldies are being aggressive.
Goldfish breed generally in 70+ degrees in tanks, but can and will at any temp. Is it the same fish doing the chasing everytime?
Thanks for the input guys!

Depot, no it's not. These fish hardly last a week in the tanks before they sell. But I'd say after every third new shipment or so I get, I notice it and have to seperate the fish. The one being chased always does look fat...

Thanks alot.
My two golds do the same thing . The gold will chase the callico around the tank with his nose at it's butt. The gold looks more agressive than the callico but I never had them sexed so I don't know if I have two of a kind or male female.
Well atleast I know I'm not the only person seeing this weird behavior. I guess it's just a mating thing. Hmm... Does anyone know what goldfish eggs look like?
Do they stick to a surface or are they laying on the gravel, do you know? I do always suck up a lot of white stuff when I clean those tanks... But they seemed kinda large to be eggs. I just thought it was small pieces of gravel. Hmmm.

Thanks for the input Depot, freefour, Zagz.
They stick, I can't see being able to vac them up when they are stuck to the gravel. They are about as large as a small ball of silica if you've ever opened a silica packet. You certainly could feel them between your fingers.
Thanks guys. Now I know the answer....mating!

Depot, these are in no way that large. They are just chunks of poorly washed gravel then like I was guessing.

Thanks again!
Top Bottom