Objectives of thesis: 1.To evaluate the effect of pH and total hardness of water on the development of eggs in aquarium fish Corydoras paleatus, Corydoras paleatus albin, Tanichthys albonubes, Tanichthys albonubes gold, Aphyosemion gardneri, Aphyosemion gardneri gold. 2.Recommendation of optimal values of total hardness of water and pH for successful development of eggs for each monitored aquarium fish. Based on published data in available literature sources and on own experiments, it was evaluated how total water hardness (CM) and pH influences development of aquarium fish eggs of Aphyosemion gardneri, Aphyosemion gardneri gold, Tanichthys albonubes, Tanichthys albonubes gold, Corydoras paleatus, Corydoras paleatus albin.