I'm not so sure that a virtual fish tank would be a Good Thing. It takes away an area of difficulty in the game. Part of the fun is in making do with the stocks of fish you have, and deciding which fish to sell to make room for more.

It is similar with the virtual seed tray in PT. Although I felt the space allowed for seeds was too small, when I had unlimited storage I thought the game had become too easy.

No disrespect is meant here to Borg, who did an awesome job on the VST, or to those who enjoy playing the game with its help, but after a while I went back to playing PT without it.