My baby fish keep dieing, I did the Environment Research... but they still die... any idea what im doing wrong?

some breeds need you to reaserch again.

1. there are 3 levels of environment research
2. environment research takes time once you start it
3. fish can die from disease .. are they spotted with fungus?

Has the research completed yet? If not, you're still at the old level of Environment (you will get a notification that it's completed). Also, you will have to get to Level 3 before all fish will survive. Many fragile hybrids will die even in Level 2 Fish Environment.

Oh ok..Im at level 2, I dont have enough money to get it done again. My fish wont sell.
Thanx for the advice

If your fish won't sell lower the price by 1-2 dollars then try again