Here is a good link to search for your fishes habitat requirements
http://www.marinedepotlive.com/
I also use the rule of thumb to add 20 gallons to what the minimum tanks size is for larger fish. So if they say "The Orange Butterfly prefers a tank of at least 60 gallons with plenty of places to hide & swim." It probably is 80 gallons. After all if we're taking fish out of the Ocean and putting them in our tanks, it's the least we can do to make sure their new home is satisfactory
