The first fry from my kribs made it just fine in the tank with the parents for about 3 months. The parents are the only fish in the tank. I noticed the parents becoming aggressive toward the babies the other day...and assumed she was ready to lay some more eggs. I set up the growout tank and filled it with the same water from the tank the fish were already in. I caught the babies and put them in the tank....I watched them for hours. They were swimming around and eating just fine. This morning, they're dead. What am I doing wrong??