Fish Identification Photos: Blue Tilapia, Oerochromis aurea: The adult Blue Tilapia has an overall “bluegill profile” with a deep body that is approximately 40 percent of its body length. The Blue Tilapia has blue-gray a body with a white belly. The dorsal fin and top of the caudal fin are red, and the soft dorsal, anal, and caudal fins have numerous pale spots. The Blue Tilapia has three or four black bars on the sides and a square (truncated) caudal fin.

A key to identification of the Blue Tilapia is that it has 20 to 26 gill rakers. Reproduction occurs via the males digging large deep circles in the sand, and females depositing up to 2,000 eggs which are then fertilized and then quickly taken up into the mother’s mouth until they hatch in 13 to 14 days as free swimming juveniles.

The Blue Tilapia has a lifespan of approximately 5 years. It is endemic to Africa and found in Senegal and the Nile and Jordon River systems and have been introduced to lakes and steams of Central America, South America, and India for use as a farmed food fish and for the biological control of aquatic vegetation.

The Blue Tilapia is the most abundant freshwater fish in Mexico and is found in all coastal Mexican fresh water streams that do not drop below 13 degrees centigrade. It is capable of surviving and reproducing in brackish waters.

The Blue Tilapia reaches a maximum size of 16 inches with the males, with better finning, being much larger than the females. It is primarily a vegetarian consuming algae. It is considered to be an undesirable exotic and release into the wild is discouraged.

The Blue Tilapia is a member of the Cichlidae Family, which consists of fresh and brackish water species which are known in Mexico as tilapia and mojarras de aqua dulce. The Cichlidae Family is a large family with more than 700 individual species. They typically have a deep, compressed body, a long dorsal fin base, and a lateral line that is interrupted and offset. They have highly evolved reproductive strategies being either mouth brooders, substrate brooders, or a combination of mouth and substrate brooders.

Blue Tilapia, Oerochromis aurea: Collected from one of the irrigation ponds of the Palmilla Golf Course, San Jose del Cabo, Baja California Sur, Mexico, in October 2007, by hand. Size, approximately 11 inches. Identification reconfirmed by H.J. Walker, Jr., Scripps Institute of Oceanography, La Jolla, Calif. Description and photo courtesy of John Snow. Blue Tilapia, Oerochromis aurea: Male. Collected from the San Jose River, Baja California Sur, Mexico, by two young locals with a cast net in December 2007. "Purchased" for a can of Coke. Size, approximately 5 inches. Identification reconfirmed by H.J. Walker, Jr., Scripps Institute of Oceanography, La Jolla, Calif. Description and photo courtesy of John Snow.