Basically I have four cometgoldfish in a ten gallon aqaurium if there growth is tainted, the smallest has gotten a lot bigger, than can they become instantes is it a permanent thing and can they still live a long and happy life once in a pond
Oooo. I would get them in a larger aquarium ASAP. I’m more concerned about water quality than I am about the size of the tank stunting their growth necessarily. Goldfish are massive waste producers and I don’t see you being able to cycle a 10 gallon with 4 goldfish in it because the beneficial bacteria can’t convert that much ammonia into nitrites and nitrates.
If it's only been 3-4 months they likely aren't stunted quite yet, they may just grow slower. However, they will have some damage from ammonia or nitrite unless you've been doing daily 50% water changes. Honestly though, you have still provided much better conditions than most get.