Incubation periods vary between the species and water temperature also affects development, but typically the eggs will hatch on the 6th to 10th night after the eggs were laid.  The eggs undergo several distinct color changes as they develop; the eyes are usually visible by day 3-4 followed by a change in overall darkening of the coloration to a orange-tan purple, followed by a silver/quicksilver color just prior to hatching.  The exact coloration may vary, but the silver/quicksilver coloration with distinctly visible eyes is usually a good indicator that the eggs will hatch within a night or two.

The aquarist need do little during this period as the adults will care for the eggs, constantly guarding, fanning, and removing undeveloped eggs.  Occasionally the adults may eat the eggs.  This is not uncommon with newly spawning pairs.  Generally this behavior abates after several spawns, but in some instances it may be necessary to separate the pair and re-pair with other fish..  During the incubation, feed normally and avoid disturbing the pair or the system (not a good time for a thorough cleaning, although some have reported that the pair seemed unconcerned with major activity by the aquarist.  EACH pair is different.