yeah and if you were nine and had a messy O in a 20g for a year your water quality wasn't as good as you thought it was and your O was severely stunted from it, now i will say that i have noticed fry grow a lot faster in a larger tank even though i did wc on the smaller tank every other day, but that is growth RATE and so is a little different, actual stunting (where their insides continue to grow but their body stops) is mainly due to water quality