Blue tilapia

Water parameters

Minimum tank: 200 L per individual at harvest size.

Feed and growth

Feed protein

32% target

Daily feed (warm)

1.40% of body weight

Daily feed (cool)

0.80% of body weight

Max density

55 g per litre

A 550 g adult eats about 7.7 g of feed per day at optimum. 10 fish at adult size: ~77 g daily.

Legality

Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.

Unlisted jurisdictions default to "check local regulations".

Origin and habitat

Oreochromis aureus is native to fresh and brackish waters of North Africa and the Middle East, including the lower Nile, the Jordan Valley and Lake Galilee, the Chad basin, and West African rivers such as the Niger and Senegal. It is one of the most cold-tolerant tilapias: it survives down to around 8 to 9 C, with half a population lost near 8.8 C and fingerlings dying off by about 6 C, while still handling water into the low 40s. That edge over Nile tilapia, which gives out a few degrees warmer, makes blue tilapia the usual choice for tilapia culture in subtropical regions where winters dip below the Nile fish's limit. It breeds as a maternal mouthbrooder, the female holding eggs and fry in her mouth for about two weeks in warm water. Introduced to the United States from the 1960s for weed control and farming, it has become a widespread invader in Florida, Texas, and other warm states, and has been blamed for native mussel declines in two Texas reservoirs. It hybridizes freely with Nile and other Oreochromis, and crosses are common in the trade, including the pale 'Rocky Mountain White' strain bred for light flesh and cold tolerance. Wild fish usually run 13 to 20 cm but can reach about 53 cm and over 4 kg.

Climate and outdoor ponds

Climate

tropical (needs warm water year-round)

USDA zones

9–13 (winter low around -7°C or warmer)

Heating needed

yes

Cooling needed

no

Care notes

Cared for much like Nile tilapia, with the bonus of taking colder water. Where a winter greenhouse drops to 12–15°C, blue tilapia keeps feeding, if slowly, while Nile tilapia would stop or die. Top-end growth is a touch slower than Nile tilapia in steady warmth, but blue tilapia often does better in systems that swing cool because it keeps eating through the dips. Feed conversion is comparable, roughly 1.5 to 2.0 on a standard pellet in good conditions, climbing under cold or salinity stress. Reproduction needs the same handling: mixed-sex groups spawn constantly and pour energy into breeding rather than growth, so all-male fingerlings from a specialist hatchery are the practical route; spawning shuts down below about 20 to 22 C. Feed a commercial tilapia pellet of 32 to 36 percent protein. Blue tilapia is often considered more aggressive than Nile tilapia, which can mean fin damage and stress when crowded, so keep stocking around 15 to 30 g/L with enough room. Water quality targets match Nile tilapia: pH 6.5 to 8.5, ammonia low, dissolved oxygen above about 3 mg/L. Legal status follows tilapia rules generally, prohibited in much of Australia and some US states, so check local regulations.

Further reading

• Aquaponics in winter: keeping it running below freezing
• Fish for aquaponics: tilapia vs everything else