BTW How Often Do Pink Convicts Spawn?
Well it really depends on when you decide to remove the fry. If you leave the fry with their parents, for say, 2 weeks. Then they will spawn again in a few days to fill the void. If you leave them with the parents indefinitely, they'll spawn less frequently.
I noticed even if I remove half of the fry for feeders, the parents will loose interest in the current clutch of fry, and immediately spawn again to replace the fry that were taken.