Tilapia are able to withstand a wide range of environmental conditions, including high salinity, high temperatures, high ammonia concentrations, and low oxygen levels. This makes tilapia very suitable for aquafarming.
Although tilapia are freshwater fish, they can grow in elevated salinity conditions.
Salinity Tolerance for Growth
|Nile Tilapia||Grows well at salinities up to 15 ppt|
|Blue Tilapia||Grows well at salinities up to 20 ppt|
|Mozambique Tilapia||Grows well at salinities approaching seawater|
Tilapia spawning is best in lower salinities. The fry perform better at salinities
less than 5 ppt.
Salinity Tolerance for Reproduction
|Nile Tilapia||Reproduce well at salinities up to 5-10 ppt|
|Blue Tilapia||Reproduce well at salinities up to 5-10 ppt|
|Mozambique Tilapia||Reproduce well at salinities up to 10-15 ppt|
Tilapia are warm water fish and usually exposing them to temperatures lower than 50 to 52° F is lethal. Blue tilapia can tolerate somewhat temperatures down to 48° F. This limits tilapia commercial farming potential in temperate regions.
|Feeding||Stops below 63° F|
|Harvesting||Stress and mortality from handling increases below 65° F|
|Reproduction||Best above 80° F, no reproduction below 68° F|
|Growth||Optimal from 82-85° F|
Tilapia are able to tolerate dissolved oxygen levels less than 0.3 mg/L, a level that would prove fatal to most other farmed fish.
Although tilapia can tolerate low oxygen levels, they grow best when oxygen levels are kept about 1 mg/L. For better growth, maintaining oxygen levels above 4 mg/L is preferable. This may require some aeration in high density cultivation situations.
Tilapia can survive in pH ranging from 5 to 10, but optimal pH is between 6
The tilapia can tolerate high ammonia. Increasing ammonia concentrations increases the stress on the tilapia.
Effect on Tilapia
|0.08 mg/L or above||Depressed feeding|
|0.2 mg/L or above||Some mortality occurs|
|1 mg/L or above||Mortalities, particularly among fry and juveniles|
|2 mg/L or above||Massive mortality|
High concentrations of nitrate stresses fish because nitrate limits the ability of hemoglobin to transport oxygen within the body. Tilapia can tolerate higher nitrate levels than many other cultured freshwater fish.
For optimal cultivation, nitrate concentrations should be kept below 27 mg/L. To prevent nitrate problems in recirculating systems, chloride concentrations are often maintained at 100 to 150 mg/L chloride.
Popma, Thomas and Michael Masser, Tilapia: Life History and Biology, Southern Region Aquaculture Center, Pub. No. 283, 4p.
Broders, Adam, Matt Douville and Megan Slonski, Best Practices for Small to Medium Scale Tilapia Aquaculture, WPI, 2005, 102 p.