Hi,
I can see you have many questions, and not many replies..
You may have already had some of your questions answered just by playing the game.. but.. here goes
After you have fully researched all the levels of fish environment (there are 3) then any fish will live and be healthy. Its a good idea to breed the "easy" ones and get some cash while your are researching. It does take some time.. but once you have finished.. you can really "play" and make all the fishies.
In my game.. at 2x speed.. it takes about 2 hours for my fish to get to age 20. that is from impregnation to adult hood.. BUT.. after you get the oriental gold bulb.. that time gets decreased if it is swimming in the tank with the babies.. I always make sure one is swimming where babies are growing up to help things move along a little faster..
Plus.. there is the growth hormone that will speed things up too.
oh.. and keep track! I have volumes of notes .. and i refer to them all the time..
hope this helps a little.. have fun.. !!
oh.. and the yellow fish is a "snout" and the white one is a "pigmy" ....