If you are keeping tetras, chances are you are breeding tetras, even if unknowingly. In the wild, tetras normally breed during the rainy season, but in the aquarium, they may breed year round. Female tetras are egg-scatters that typically fill with eggs every ten to fourteen days.
The female tetra indiscriminately sprays her eggs into clumps of fine-leaved plants. The eggs are adhesive and stick to the plants. However, tetras as well as other tank mates often find tetra eggs and small fry an irresistible delicacy.
If breeding tetras is your goal in keeping them, the best thing to do is to separate males and females. This allows you to keep control of breeding and improves your chance of achieving a successful hatch of fry. Smaller species of female tetras become sexually active at nine to twelve months old with larger species ready to breed at 1