Nice game,
I'd like to see

1. "Clickable" Parent fish to show info (ie: clicking on any of the 3 fish in the Species windows will display the Fin Fish type of that fish) - not just the name of the offspring

2. One time price modify on all fish in the selling tank (ie: i want to sell all my fish for $5 each b/c i need room quickly and i don't need the cash)

3. Tracking library of the types of fish/fin that i have encountered.

4. Enhance stat to include the fish that sold with the highest price and the price