I'm trying to find the generalized rules for goldies. I know 3 years ago I was told 30g for each single tail and 10g for a fancy. Is it a 2 gallon per inch of fish rule? Also does filtration change the rule? I know that the fish become stunted when they don't have enough space and that filtration probably doesn't siphon all of the (hormone? enzyme?) that tells the fish when to stop growing. Please direct me in the right place!