I think you could have caused a little bit off stunted growth. I did keep two fish in a ten gallon tank a year ago for six months and theyre about an inch of lost growth.

You can put three goldfish in there. Everyone has different rules right now on the forum so it doesn't really matter who you listen to. Yes a betta would do fine in that size tank.

As far as the gallons you need for your fish, there are diferent ways as faintailer said. Both of these are a little different, so you can decide what works best for you.   Look at your fish see if there is any noticable damage, like eyes buldging, his belly swollen, I can't think of all the symptoms of stunted growth. Have you been adding any bacteria to the cycling tank, to help with the building of benificial bacteria? This will help with building the bacteria, to kill the ammonia, nitrates, & nitrites. Orandagal is right it is very addictive, & costly, but well worth the work!! I started with 37 gallon moved to 55, then got another 37, then a 60, now I have 150. I had to get rid of some of my tanks, but I still have the 60 & 150 gallon tanks. So take your time things will come together, & your fish will beh healthier if you wait for your tank to cycle.

Yeah thats what I was wondering fantailer...but he still is very small he is around an 1 in and a half. And yes I did add bacteria I have had tropical fish before and Ive always found it easier and safer to cycle without fish in the tank  As my fish looks though he looks the same since I got him...just slighty larger  I got him at a pet supermarket a town over they actually had alot of variety and healthy looking goldfish for being a large chain! I just feel bad about putting him in such a small tank But you guys have really helped me so I thank you!!!!

Hi and welcome to the forums!

I think from keeping a goldfish in a small tank, as you've stated, yes, it's growth will probably be stunted, so the fish will quite possibly grow at a slower rate than a goldfish of the same age kept in a larger tank.

I personally kept a goldfish in a 21 litre tank for around 5 months where she grew an inch or two (she was around 3 inches in total by this point) she's now in a 90 litre/3 foot and has grown around 1/2 an inch, in the 2 months she's been in there.

Seeing as your goldfish has been in the 1 gallon tank for a small time and I imagine will be moved very soon, he should be fine
As long as you see no outward or behavioural signs of him being unwell, as often fish kept in small aquaria have generally had to put up with poor water quality and can have some problems because of this.

Do you have a water test kit or a pet store that can test your water for you? This can be really helpful with knowing when the tank has completely cycled   It could also help on knowing what the water quality on your 1 gallon tank is like, if the water quality is bad i.e. ammonia/nitrites present, or nitrates being above 40ppm, then you may need to do more regular water changes while the bigger tank cycles.

Best of luck with cycling! Look forward to seeing some photos