Fecundity is the ability of fish to produce eggs. The process of laying fish eggs is called spawning. Roe fish lives in stagnant water but lays its eggs in flowing water. It is called protamodromous. The suitable environment for egg laying is water temperature 24-280 C. And water contains a lot of oxygen. Cotton fish lays eggs on Amavasya or Purnima. At this time, the male fish secretes steroid hormones into the water and attracts the female fish for reproduction. The female fish lays about 19,00,000 eggs in the turbid water under the obsessive effect of retaxis. Eggs that float in water are called pelagic eggs and eggs that sink are called demersal. Dr. Siddiq Publications