This research studied the effect of water temperature increase on male O. niloticus experimentally and survey. One hundred male O. niloticus delivered from private farm fish divided into four groups: 1 st kept at room temperature (Control) and others at 30, 33, and 36 ºC for 2 weeks. Two Survey groups collected from El-monib at 27 ºC (Control) and at 36 ºC water temperatures.
Experimental fish suffered from nervous manifestations, detached scales, ulcers, tail rot. Unsymmetrical testis which appeared thread like especially at 36 ºC and survey. 
Growth measurements revealed highly significant drop in B.W., WH and WG. In addition, relative fecundity F.B.W. and F.O.W (only at 33 ºC) registered highly significant decrease. Sperm density and sperm live % also showed highly significant drop.
On the contrary, survey group B.W., WG, WH, and IG as well as parameters of relative fecundity (F.B.W. and F.O.W) showed highly significant increase. Oppositely, Sperm density and sperm live % copied highly significant decrease.       
At 30 ºC and 36 ºC water temperatures and survey total protein and globulin decreased highly significant. Estradiol hormone decreased highly significant at experimental and survey groups. Glucose and testosterone increased highly significant at experimental and survey groups.
Malformation and distortion of seminiferous tubules with a lesser number of sperms. Hepatic cells appeared swollen with vacuolar degeneration.
Favorable water temperature for Oreochromis niloticus to achieve their maximum reproductive performance and their health is 27 ± 2ºC.
Thus, recommendation to increase aerators in broodstocks ponds or to be covered during the summer season