I don't play Fish Tycoon alot anymore because I get frustrated having all the types of fish to make what I want and nowhere to put them. I just keep pairs not 10 of each,,lol. I hope Borg will make us an extra tank. I am 67 and have arthritis up the kazoo and wish I had Borgs knowhow and talet. Common baby u can do it.Hugs from Emoto

Are you playing the full version game? It has three tanks
If you are, try to sell the fish you don't need. Maybe in the future a fish tycoon sequel will be made, but for the time being, try looking at some answers for magic fish if you like.
Enjoy the game and welcome to the forums!

I believe Lady said before that that FT was made differently than their other games, and because of that there can't be mods for it.

There can't be graphic mods for Fish Tycoon, since the images are not accessible outside the game. What's being described here is not a graphic mod, but would require reprogramming the game. That's not possible for users to do with any of our games.

I just wanted to add...

Surely the whole point of the game is to discover all the fish using the 3 tanks available? It would be a lot easier if there were more tanks, but that would spoil the challenge wouldn't it?