I know that comets need 20 gallons and fancies need 10 gallons min. to grow properly and stay healthy. And I know GF are very messy fish and poop like crazy, and that doing water changes that are too big and/or too frequent can mess up your cycle, but is there anyway you can have them in a smaller tank without stunting their growth and keep the water and fish really healthy? How long can you house them in smaller tanks before you stunt their growth? I am just curious and have wondered about this for a long time.

it's not recommended to overcrowd goldfish in a tank too small.
if there is absolutely no other option though...
than it is important that you test their water daily or even twice daily...
and keep up with water changes to keep the water quality pristine clean.

why do you ask?

if your budget doesn't allow for another fishtank and your tank is overcrowded...
there are plenty of other options...
rubbermaid tubs make for great makeshift tanks.
HOB filters hang perfectly on them as well.
i'm sure there are many members who would be able to give tips too!

::edit::

costco also currently has 100 gal rubbermaid stock ponds for $59.99
haha i almost got one today had it not been for beancurdturtle's advice...
he kindly reminded me that i would have nowhere to put it if/when i move.

Just asking because I have 7 of the fish I rescued (not bad since there were 19) left that haven't been adopted yet and they look so cute playing together that I am sad to split them up (I was going to keep 2). They actually waited in a line to play in the water flowing from the filter, and took turns! My kids could have taken lessons! We don't have the money to buy a bigger tank, especially not a 140 litre tank, nor to we have anywhere to hold one. I am not actually going to keep them all (just dreaming) but my tank is too small to hold 2 of them and since we sold our house and have to move the beginning of July, and have not yet bought a new one, now is not a great time to think big or think pond. If we had a house to move to that I could put a pond in, I would so do it!! That's one dream I have and it will have to stay a dream a little longer...but hopefully the local costco will have the pond if we find a house where I could fit one...

It's too bad that we can't push the fish limits hey? I tried for a little while a few years ago. I rescued a bunch of fish as well, and ended up with 4 in a 20 gallon. Even with all the info from this site, I couldn't make it work. If I got busy at work/school and missed a water change...just once, things went down the tubes and the water quality crashed.

I would consider a rubbermade if I were you. The fish don't care what they're in
You could keep them nice and happy in there until you can afford a larger tank (and by the way, check your local classifieds, etc, you can get real deals on used tanks)

I agree whith all that has been said. BUt, there is a tremendous difference between keeping a fish in a 5 gallon tank and keeping 7 in a 55 or 60 gallon tank. As the volume of water gets larger, there is a little more wiggle room for keeping the fish for a time in crowded conditions.

There is no way you can sufficiantly filter or change out the water for a large fish in 5 gallons. But I do think that you can, with great care, loads of test and work, keep more in a large volume - numbers that are greater than1 per 10. Is it good? Not particularly. If you fail to test, change, filter and monitor the tank very carefully things go wrong. In a more lightly stocked tank you have a bit of time to react and fix a problem. When things go wrong in an overstocked tank, they go wrong fast and BIG. You can lose the whole population in a very short time.

So - no it is STRONGLY recommended thatyou do NOT overstock. BUT..... if you have no other option, the larger the volume that you use, the better. I have 5 in a 40, 5 jumbos in a 60. Those tanks are overstocked - and soon to be adjusted. But for the time being I can do it. I could not do 1 in 5 gallons. The big stock tank - Rubbermaid - sounds like an excellent option. It may not be "officially" big enough, but because it is of fair volume, with care, you should be able to manage it - at least for a time.

Thanks for the tips and info. I have always kinda wondered why the "rules" are as they are. Right now I am doing daily water changes and trying to find homes for them. It is harder to find homes for these last 5.
One question, How do you get the filter to work properly on the rubbermade? I can't get it on properly and my hubby would kill me if I bought another (I just bought one since I couldn't find my spare). My biggest is a Penguin bio-wheel for a 20 gallon (GF requirements). I am cycling the new filter so I can switch it with my other one (the Penguin is on my 10 G tank with tetras and cory's so I have to cycle the new one first so I don't kill my tetra's). I am still looking for my spare, but it is only a quiet whisper for a 10G, but if I can find it, and fit it on the rubbermade with my new filter, it would help filter much better.

The fish are still doing great and the water quality is still good (let's hope all the Cycle I've added and keep adding will help it cycle quicker). I added an old air pump to help increase the air, and they seem so happy and healthy, so far at least.

The biggest rubbermaid I have is a 70 gallon, and wihout a filter, they were so unhappy in it, mind ya that was with 15 of them in it.

Thanks again!!

Just saw this thread... this part of your premise is incorrect. You don't want to scrub out your filters or entirely clean of your rocks or do anything to disturb the surfaces that the cycle bacteria grow on, but as for the water changes themselves, there is really no thing as too big or too frequent... well, I guess changing 95% of your water every hour might start to annoy your fish, but that's about it.

Other than that, the only concerns I can think of are if your new water isn't properly temperature matched with the current tank, or the pH or your tap is different from your tank and it causes too big of a pH swing. But nothing has to do with hurting the cycle really.