All you have to do is pick the amount of eggs and then watch. I made this as realistic as I could, so I hope you like it! When you press food, scroll anywhere in the deep water and press space to give the adults food, but the babies eat yolk from the eggs until they go to the top (which in this case, means that they are adults.) You don't have to feed them to make them survive, so don't worry about that. As I say below: "Sorry for any bugs!" I had to do a fair amount of research to make this! You can try turbo mode (Shift + Green Flag) If you only have one fish, it probably won't reproduce, it might, but if it is a male, it won't. I would recommend starting with 3-4 fish. They will die, at a maximum of 11 years alive (That means 12 years of the generation). Don't worry at the map scene, you have to wait a year (A.K.A 10 seconds), it didn't freeze. Sometimes the trout pop up before the map closes, I don't know why, but it just happens, but not for long.
***PLEASE READ AND RAISE AWARENESS*** In school, every year, the fifth graders at my school used to raise Steelhead trouts and then release them into the wild right before their migration. This year and last year, because of a drought, we couldn't do it. I felt like I should raise some awareness to these fish, because they are endangered now. I tried to make this simulation realistic, but there are a few things that I left out. For example, in real life they can jump up to 12 feet in the air! I did EVERYTHING in the project, so the animation isn't the best, and the coding is only so good. Sorry for any bugs. For example, if none of the eggs that you added were female, which is highly unlikely if you use 3 or 4 eggs, they can't reproduce.