The thing about keeping a snowflake in a 3 foot tank is it's going to get the length of it eventually or nearly so, and it should at least be given an option to travel from one cave to another. Also, if it gets really excited during feeding time, where in a 3 foot tank are the tank mates going to hide from a hungry 3 foot eel that smells food? The length limits you, imo, to probably just a dwarf, chestnut, or jewel moray.
Now if you wanted to keep a snowflake in your tank, it's not like it would stress to death. They're bullet proof. Just imo a smaller species would probably be happier.