Hi. I have tried several times now to breed my neon tetras. I place the conditioned male and female into the spawning tank, the fish do indeed spawn, but the eggs always fungus.
The tank is covered with newspaper and a dark towel over the top so that it's nice and dark inside. It is covered in this way as soon as the fish are introduced to the tank (so they are also spawning in darkness), and the cover is never removed allowing any sunlight in.
The tank is filled with 100% rainwater.
The fish are over 1 year old, so I assume they are mature enough.
What could the problem be? All the eggs fungus within a few hours of being layed - I am guessing that they are infertile.
I have tried different males - could all my males be infertile?
Water temperature is 25 degrees C - is this too warm?
Rainwater - so no hardness issues.
pH - I have tried neutral and also have reduced it down to pH 6.0 - eggs still fungus.