how long until goldfish outgrows tank?

I have recently set up a 10 gallon tank, and have now added a fantail goldfish. I understand the nitrogen cycle and know how to keep the water quality up. I am just asking how long he will be able to live in the aquarium before he gets to big. I know the owners of my local fish store and am able to return the fish when he gets too big and replace him with a smaller one.
-J.C.

 

Welcome to the forum and glad you joined us. A 10 Gal tank is way to small for a goldfish even for a short time a fantail should have at least a 40 gal tank. You might want to return him and get some smaller fish for your tank, a betta would work a few , or a few male guppies or male platy fish so that you don't have any fry. In the stocking section on the forum page in the grey area is a sticky on Stocking options for a 10 gal tank with lots of ideas. Have a read on that for some good ideas. Alison

 

Like AlI said, that's not a good idea and it doesn't make sense to get fish that you know are not the right size for your tank. It's not fair to the fish.
Either upgrade the tank size or just get more suitable species. There are lots of options.

 

How is it not fair to the fish if he will be transferred to a bigger tank when he outgrows mine? Which brings me back to my original question.

 

Its like getting a puppy and rehoming it after it geta larger..
I agree. Get a fish for your tank size

 

When fish are in too small a tank for them it will cause growth problems in a short time. It is called stunting. And interferes with their long term health. Alison

 

Agree with everyone here, it's honestly horrible that fairs gave away goldfish and all, they basically told children(who grew into adults and passed this on) that it's perfectly OK to stuff this fish that gets a foot into a one gallon bowl, here you go! Sorry, the people who started this bad of goldfish just irritate me sometimes... Well anyway, I'd suggest getting a bigger tank ASAP or returning him. But my question is, if you where to get a 29g, would you be ok with just having one fish in there? Personally though, I'd be getting stressed seeing the goldfish swim around in a 10g, but that's just me. To your original question, it wouldn't "outgrow" your tank, instead like aliray said, he would be stunted. Honestly I'd really only be ok with keeping in there for a week. But with daily waterchanges you might be able to keep him in there while your getting a bigger tank set up.
Welcome to the forum by the way.

 

We did provide an answer to the original question - it's not suitable to leave a goldfish in there at all.