The size of the nest is dependent on the size of the fish and should be considered a factor when stocking in lakes constructed with liners. Nesting holes up to 3 feet deep have been noted. Eggs are laid and fertilized in the nest and then watched or held in the males mouth until hatched, hence some species are called mouth-brooders. Hatches of several hundred to several thousand offspring occur in six days. The T. zilli spawn at a greater rate than the T. mozambique which spawn a higher percentage of male offspring.
Some species feed only on microorganisms while others also feed on plant materials.
Most of our interest has been with mixed gene pools which, due to their voracious appetite, will control chemically resistant blue green algae's, i.e. lyngbya, which are a common nuisance in the Southwest. 1-3 inch Tilapia will tend to consume more nuisance algae than larger fish. Most Tilapia will also consume insect larvae, crustaceans and decaying organic material. When stocking with bass allow tilapia to become established prior to introduction of bass.