Mixing Goldfish

[DrummerGirl]

I have 1 Goldfish now, I was planning to get another one in about 3 to 4 months and put the both of them in a 30g tank together.

Is it a bad idea to put a new baby Goldfish in a tank with a 4 - 6 month old Goldfish?

[becky_e]

It never was a problem when I did it. Also, you can buy bigger goldfish at many fish stores that match the size of your goldfish better. I've never put a tiny goldfish in the tank with my large ones, but the large one I had was an 8 inch long oranda that I had for 7 years at the time. The smallest goldfish that I added to the that tank was about 2 inches long and they got along fine.

I strongly recommend quarantining the newcomer for a while before you add it to your existing fish's tank. I had never heard of quarantining when I added 2 new goldfish to my 45 gal with the big goldfish. They brought a parasite to the tank and the newcomers survived it but my 7 year old oranda didn't!

[aquariumfishguy]

I'm really not sure a "4 - 6 month old Goldfish" would be much larger than a (so called) "baby goldfish", anyway. I think it would be fine either way. Definitely quarantine first though.

[Peekaboo]

I've put in a tiny feeder goldfish with a 4 inch goldfish and they were fine together.

[Nuriel]

most goldfish grow pretty big- I suggest either geting different tropical fish or just sticking to one, unless you plan on giving them away when they get too big for the tank. :)