 Once spawning is completed, it is advisable to keep the aquarium under dim lighting conditions until the eggs have hatched and the fry are free-swimming.While rummy-nose tetras do not need their eggs to be kept in total darkness as is the case for neon and cardinal tetras, the eggs are known to exhibit some degree of photosensitivity, and subdued lighting is highly advisable during egg development in the breeding aquarium.Fertile rummy-nose tetra eggs take approximately 72 to 96 hours to hatch at 32 °C.