Solving the Problem of Lost, Free-swimming Fry
Your breeding pair of discus has spawned, the eggs have hatched, and the parents have successfully guarded the wigglers. But for some reason, when the wigglers become free-swimming, they can’t seem to find the parents. They scatter around the breeding tank. This is a common problem, especially with some of the Pigeon Blood strains of discus. If the free-swimming fry don’t find their parents, they will eventually perish. Here’s what I’ve had success with when this has happened to me.
1). Lower the water level to one-half of the tank volume, but no lower than the lift tube of your sponge filter. By doing this there will be less water volume for the fry to swim through, and easier for them to find their parents. Make sure you’re using a submersible heater that is placed on the bottom of the tank so the heater won’t break.
2). Turn the airflow way down in your sponge filter, but not off. This will create less turbulence in the water so the fry will be attracted to the movement of the parents. I have seen some pairs twitch their bodies and fins, to call the fry.
3). Place the spawning substrate on the opposite side of the tank away from the sponge filter. Cover the side of the tank closest to the spawning cone with paper or cardboard including the top. This will create a cave like affect.
4) Using a small aquarium light fixture, light the uncovered side of the tank, closest to the sponge filter. The fry and parents should go to the dark side of the tank and hopefully have a better chance of finding each other. The fry should find their parents and start to feed from their slime coat. If they do, then leave them alone for the next twenty-four hours. Then you can slowly fill the tank a few inches each day. Make sure to use clean, aged water that is the same temperature and be sure it has no chlorine or chloramines present.