Some advice about adding another cold water fish in the tank with my fantail and goldfish?

Question

I have a fantail and a goldfish I want to add another cold water fish , my current 2 have been together since I bought them, will they fight with my new fish? Is it ok to buy another fish, my tanks big enough and all that, is it the right thing to do?

Answer 1

Goldfish grow very large (despite the misinformation freely given by uneducated salespeople that allege that a fish will only grow to the size of its tank). Your fantail will grow to be 8-10 inches in length (not including the tail) and live for 15+ years provided that it has an adequate housing situation. Common (single-tailed) goldfish can grow up to 2 feet in length but usually settle in the 10-14 inch range.

Your tank should be no less than 40 gallons for these fish.

The primary issue I see with this scenario isn't necessarily the size of the tank, but the behaviorism of the fish in question. Fantails are selectively bred for showy fins and bulbous body shape. This makes them a very slow-moving fish compared to their common cousins. They cannot obtain food particles as easily as the common so when housed together, the commons tend to gobble up everything while the fans get meager portions (if that).

If you're going to keep multiple goldfish, you need to be keeping only fish of the same size and type together to prevent potential problems. You also need to be certain that your tank can handle the demand that will be put upon it with housing multiple goldfish. Goldfish produce quite a bit of waste and when kept in an inadequately sized tank, you will undoubtedly have ammonia-related problems.

Answer 2

Well, goldfish can only really be kept with other goldfish. The only thing I can think of you to add is an apple snail. They can live at cooler tempuratures. If the tamp is lower they live up to 3 years and reproduce less often, if the temp is higher they live about a year to a year and a half and repoduce often. Don't worry, you have to have 2 and you have to lower the water level for them to reproduce. Do not add tropical species tho!

Answer 3

How large is this tank? For two goldfish you need at least 30-35 US gallons.

Only goldfish can be kept with goldfish. Is the regular goldfish a common/comet? In which case it will outgrow the fantail, outcompete to food, possibly bully it and injure it. You shouldn't mix fancy and common goldfish.