They will breed if they feel like it but if they don't feel like it - then tough cheese :lol:
I had mine 3 years with nothing, then suddenly they bred prolifically for a year or 2 then stopped again. 5 years later, fry have started appearing again :roll: . Nothing had changed in the tank or with the maintenance in that time.
I have no idea where mine lay their eggs as I have never seen them. The only way I know they have been up to something is when I suddenly notice fry zipping all over the place! Others have found they prefer tight spots under, or in, logs or rocks or similar hiding places.
They don't seem to care how many of each sex you have, as long as you have at least one of each to start with
Dad looks after the eggs and fry but they are pretty much on their own once they have absorbed the egg sac. They have large orange eggs and the fry are a good size when hatched. Fry wil happily suck on algae and wafers alongside the parents and other bottom feeders.