I have fish tycoon on my iphone and at first i loved the game but in the last few days I have had to start over numerous times because the fish die constantly. I dont understand what is going on.

There are a number of things that can cause dead fish. First, you can overfeed them. If you feed them before they are hungry (about halfway down on their "Fed" meter), they will lose health each time you feed them.

Fish can also lose health and die if they are too fragile to survive in the level of Fish Environment that you currently have. Only the common fish (the ones that you can hatch from common eggs) can remain completely healthy in a Level 1 Fish Environment. The very fragile hybrids will usually not live to adulthood. Vitamins will temporarily improve their health, but only the proper Fish Environment will solve the problem.

Of course, sick fish will die if you don't cure them, and diseased fish can infect other fish, compounding the problem!

They are only living to be 9 to 11 hours old. This is odd becuase when I first purchased the game I was able to get much further.

Any further ideas.

What level of Fish Environment do you have and what species of fish are in the tanks? Did you sell all the fish you started the game with and keep only the babies you bred? If your fish are living only to that age, it's most likely that they are fragile hybrids.