I think it would be nice to have multiple games/profiles as well as the ability to reset a game.
As some of us only have one smart device and allow our children or others to play on it as well .. there is no way to lock purchases so that someone else playing can not either make purchases or spend coins/gems one has bought.. and a reset / start over or additional user names would help curtail such issues.

For instance: I may have a project of breeding all fins of one species and someone else picks up my phone .. sells them all cause they want to try for magic fish #3 or something then I have lost all my progress and necessary ones I needed to finish have been sold as well as the ones needed to make them .