i just started and im tryin to breed my Speckled leaffish (i got it from breeding a few together...) so i can sell them in mass quantities.. i found that they easily sell for 80 cash in no time... but whenever i breed them together they produce a baby fish that dies... however i can still breed multiples of it from its parent fish...

when two identical fish are bred together, does it not produce a fish identicle to the parents?

Yes, breeding identical fish produces offspring that are identical to the parents. What level of Fish Environment do you currently have in the game? That fish is a fragile hybrid, and won't live indefinitely in a level one environment, although the babies should live to adulthood. Are you playing on a higher difficulty setting, perhaps? What version of the game are you playing?

im playing version 1.01 i think, and they live pretty well, they also sell for 90 gold if i increase the price (and i dont even have to wait longer for them to sell)

now that ive made about 2000 cash off of em, im researching environment, and have the second tank...

its weird, sometimes the babies die when they come from the two identical parents, and sometimes not.. but they never die when its 2 species making it...

Edit: oh and im on medium difficulty

It's probably due to small differences in the hardiness of the individual babies. Have you tried getting the temperature regulator and the aerator? They can really help, too.