When you're still in level one and don't have the green-fin spotanus twice, I always try to make the speckled Goldshark. Although not exactly a level one fish, it survives 2-3 breedings at least and gives you $36-39 each!With each breeding I sell the parents and keep some of the young ones for the next batch. That way, even in level one you can make money fast....In higher levels the Crimson Comet sells for as much as $95 and of course once you found it the Golden Guppy beats everything!
Apart from money making I love the grouper and the catfish.

Marjan