View Full Version : strange goldfish behavior

03-28-2004, 9:06 AM
I've had a Goldfish alone in a tank for about a year now and we recently decided to upgrade his tank and put in another goldfish. The problem his that the old goldfish is pretty much constntly chasing the new one around. He does not seem to be nipping his fins, but puts his nose against the other one's rear end and pushes him around the aquarium. At feeding time both fish get their fair share of the food, they are not fighting over that. I should also mention that the old goldfish is rather bigger than the new one, by about 50%. Are they fighting, or simply playing? Should I separate them?

Thanks for your help

03-28-2004, 9:21 AM
How much is it going on?
If the smaller one is being harrassed to the point of not being allowed to rest, then I would separate them. Otherwise I would probably do some careful "watching and waiting".

But then I have no experience with Goldfish breeding habits...
Is the larger one showing any "breeding stars" on his gill plates or pectoral fins? That'd be a clue that something is happening, and it is spring :confused:

He's probably just happy to have some company :D

03-29-2004, 3:19 PM
This COULD be breeding, but if it's constant and you noticed it after transferring them I would question whether or not its more a territorial issue than anything. What size tank are they in, I dont remember you telling us. Ideally, these fish should have 20 gallons per fish which would mean a 30-40 gallon aquarium for just 2 Goldfish.

03-30-2004, 5:39 AM
The size of the goldfish should have nothing to do with the chasing. Being territorial will cause the chasing or a breeding session would. The territorial part can be easily fixed with changing the decorations around. Moving a filter from one corner to the other side or rearranging your plants should do the trick. As for the breeding, you need to check the big fish for breeding stars; it looks like little white bumps on his gill plate on either side. If this is the case then I would try to do 3 things, one would be if you have a heated tank lower the temperature in the tank slowly and slightly to slow them down; second would be easing up on the feedings: three if one and two fail separate them for a little while.

Breeding stars picture (http://www.kokosgoldfish.com/forum/index.php?act=Attach&type=post&id=132485)

03-30-2004, 3:43 PM
Avoxo - I see your point, but what Cearbhaill says also makes total sense. I mean, little goldfish cannot defend themselves like the bigger guys can. This is why the fish should be around the same size when introduced...especially if space is a concern.

Additionally, the type of Goldfish can have a lot to do with things. Comets are faster, and generally more aggressive than Fancy Goldfish. This is why many avid Goldfish keepers will tell you they recommend the same species kept together unless AMPLE room is given to even things out. Just a thought. ;)

03-31-2004, 9:43 AM
Cory, I agree with the tank size but francois has not stated what size tank he or she has. Goldfish are a passive fish, meaning that any size fish can be put together in the same tank. I would only worry about the size difference is if the smaller one would fit into the larger one's mouth. The only time I have seen goldfish become aggressive to each other is at feeding time or an introduction of new into an already established tank.

Keeping different types of goldfish such as comets with orandas is ok. The only ones that I would try to keep separate would be the more delicate varieties such as bubble eyes, celestials or maybe even some the more high quality lion heads or ranchus.

03-31-2004, 4:03 PM
I see what you are saying, and I am glad you have had such (presumably) good luck with your Goldfish.

However, as I said, unless the goldfish are in a very large aquarium the bigger fish can be known to pick on the small guy. Same goes with fancy goldfish such as Orandas Vs. Comets. Comets are faster, can reach the food easier, and are bullies at times. JMO based on JME.

03-31-2004, 5:18 PM
Why are you throwing shots for Cory? Not very nice at all Cory. Are you going to do the same thing over here like you have done in other forums Cory.

04-04-2004, 12:25 PM
Francois if your have the room in your tank you can always put another goldfish in and see what happens