it isn't a big deal to keep seperate bloodlines or strains going. i maintained several seperate bloodlines of discus and would cross the F1 progeny to maintain the fertility and bolster the immune system when i was raising them commercially.

once females start spawning, and they will produce eggs with or without a male present, their growth slows drastically in cichlids. females can be brought into spawning cycle by water temp, water quality, altering pH, food conditioning, and other females in cycle in the same water system. fish will spawn if all conditions are right and if the conditions are extremely poor to preserve the species.

a closed system like you all use allows the hormones and feramones to build up in the water; they are not removed by plants, gravel or even for that matter with GAC (granular activated carbon).

i played with mossambicas for the aquarium industry in '72-75. no market, but they were extremely intelligent fish that were easy to train to thump a device to get food and to run mazes.