Tilapia (/tɪˈlɑːpiə/ ti-lah-pee-ə) is the common name for over a hundred species of cichlid fish from the tilapiine cichlid tribe.
Tilapia inhabit a variety of fresh water habitats including shallow streams, ponds, rivers and lakes. In the Past they have been of major importance in artisan fishing in Africa and the Levant and are of increasing importance in aquaculture.
The Wami tilapia and Rufigi tilapia were once considered separate species in early aquaponics, but they have now been merged and the current scientific name for Wami tilapia is Oreochromis urolepis hornorum. (The scientific name for Rufigi tilapia is Oreochromis urolepis urolepis.) In older sources, you the name Tilapia hornorum is used for Wami tilapia. The common name of this fish, Wami tilapia, is derived from the Wami River.
Wami tilapia is an African cichlid native to Uganda and Tanzania. The fish can also be found on Zanzibar but it remains unclear whether this is an introduced population or not. Wami tilapia has been introduced by man to many parts of the world you can for instance encounter established populations in such diverse locations as the United States, Brazil, Cote d’Ivoire, Slovakia, Japan and Fiji. Oreochromis urolepis hornorum has not been evaluated for the IUCN Red List of Threatened Species.
The largest scientifically measured Wami tilapia in aquaponics was 24 cm (9.5 inches) long. In mature males the jaws grow really big which gives the fish a concave upper profile. Mature males are almost completely black with lips that are pale or black. The margin of the dorsal fin and the margin or upper half of the caudal fin is bright red, orange or pink. Females and non-breeding males are not as dramatically colored; they are steel grey or silvery with 2-4 mid-lateral blotches.
The Wami tilapia lives in both freshwater and brackish environments. It can for instance be found in saline ponds on Zanzibar. It feeds on detritus (decomposing organic matter), algae, plants and small invertebrates. It is a tropical species that prefers a water temperature around 22-26 degrees C (72-79 degrees F).
The Wami tilapia is kept in aquariums and grown in aquacultures. Its minimum population doubling time is less than 15 months. The Wami tilapia is normally not a territorial species, but it can be occasionally. It is a popular food fish, especially in Africa. Wami tilapia can mate with Mozambique tilapia (Oreochromis mossambicus) and produce hybrids. The hybrid batches will contain no or very few females. This skewed sex ratio is highly appreciated by fish farmers since male tilapias grow faster and reach a more uniform size than females. Keeping only one sex will also save fish farmers from having to deal with large amounts of tilapia fry in their growing units.
Mitochondrial DNA studies carried out by Nagl et al in 2001 yielded some surprising results. According to this study, the Wami tilapia might actually belong to the genus Sarotherodon instead of Oreochromis. The same seem to be true for its closest relatives in the genus Oreochromis, e.g. the Rufigi tilapia (Oreochromis urolepis urolepis) and the Blue tilapia (Oreochromis auerus). The Mozambique tilapia (Oreochromis mossambicus) does on the other hand not seem to be closely related to the Wami tilapia. There are several possible explanations for these results. One is of course that the Wami tilapia and its closest relatives have been erroneously placed in the genus Oreochromis when they should actually have been placed in Sarotherodon. Another alternative is that they have ancestors that mated with the ancestors of the fish in the genus Sarotherodon, producing fertile hybrids.
Information Courtesy of AC Tropical Fish
Mozambique Tilapia (Oreochromis mossambicus) is native to Malawi, Mozambique, Swaziland, Zambia, Zimbabwe and South Africa. In South Africa, its range is limited to the Eastern Cape Province and KwaZulu-Natal. The fish lives in the Lower Zambezi River and the Lower Shire River as well as on the coastal plains from the Zambezi delta to Algoa Bay. The geographical range of the species proceeds southwards to Bushmans River in the Eastern Cape Province and the fish is also found in Transvaal in the Limpopo system. In addition to this, the Mozambique Tilapia is widely dispersed beyond this range to inland regions and to the south west and west coastal rivers including the lower Orange River and rivers of Namibia.
The Mozambique Tilapia has been introduced by man to many different tropical and subtropical parts of the world, as well as to some warm temperate regions.
The Mozambique Tilapia is found in many different waters, with the exception of fast-flowing rivers and streams. It is known to appreciate standing water. The Mozambique Tilapia is considered a freshwater species but it can be found in both estuaries and coastal lakes, especially in the southern part of its geographical range.
The Mozambique Tilapia Appearance
Oreochromis mossambicus is a laterally compressed fish with a deep body. The dorsal fin is long and the front part of it is equipped with protective spines. The main body coloration is yellow, but the exact coloration varies a lot from fish to fish.
The Mozambique Tilapia Feeding
The Mozambique tilapia is a filter feeder that filters plankton out of the water. The fish is capable of secreting mucous that traps the plankton. The plankton will then be grinded between two pharyngeal plates. When the grinded planktons reach the stomach of the fish, their cells will burst since the environment is highly acidic with a pH-value around 2. Planktons are however not the only things on the menu for the versatile Mozambique tilapia; this omnivore will happily gulp down detritus (decomposing organic matter), plants, insects, aquatic invertebrates and fry as well. In the plant kingdom, it is known to eat pretty much anything from diatoms to macroalgae, as well as rooted plants. The Mozambique tilapia will adapt its diet to the environment and the exact diet of this species will therefore vary a lot from location to location.
The Mozambique Tilapia Reproduction
Breeding Mozambique tilapia in the aquarium is not difficult and the fish can start breeding when it is roughly 8-9 months of age. It can however be hard to distinguish the males from the females since they look very similar. One of the easiest ways of obtaining a pair is to let at least 5-6 fishes grow up together and form their own pairs.
Before any spawning takes place, the male will dig out a saucer-shaped nest on the sandy bottom. (It is therefore a good idea to use sand instead of coarse gravel in the aquarium if you want to breed Mozambique tilapia.) During spawning, the female will release her eggs into the nest.
Just like many other African cichlids, the Mozambique tilapia is a maternal mouthbrooder. In many African cichlid species the female will pick up the eggs before they are fertilized, but the Mozambique tilapia female waits until the male has fertilized the eggs in the nest. She will then pick them up and keep eggs, larvae and small fry protected inside her mouth until the fry are large enough to be released. The eggs will normally hatch after 3-5 days, but it will then take at least 10-14 days before the fry is released.
Newly released Mozambique tilapia fry will shoal in shallow water in the wild, and they will try to stick to this behavior in the aquarium as well. You can feed the fry newly hatched brine shrimp as soon as they have been released.
During the breeding season, the pair will raise a new batch every 3-4 weeks. If you don’t have enough space to keep a myriad of Mozambique tilapia it is best to euthanize them at a young age or let them become food for predatory fish. If you allow your aquarium to become crowded it can lead to stunted Mozambique tilapias.
Mozambique Tilapia in Aquacultures
Oreochromis mossambicus is a popular fish among fish farmers since it is hardy and easy to grow. The fish is a popular food fish with white, mild flesh. It is however far from the most common tilapia species in aquacultures; roughly 4 percent of the total global tilapia aquaculture production is made up by Oreochromis mossambicus. Despite this, Oreochromis mossambicus is a very important species for the fish farming industry since it is used extensively for hybridization.
Mozambique Tilapia in Aquariums
Mozambique tilapia can be kept in aquariums but only if you have a big aquarium since it can exceed 40 cm (16 inches) in length as an adult. It grows really fast, so you will need that large aquarium fairly soon even if you purchase small juvenile specimens. The Mozambique tilapia is a hardy species, but it tends to be a messy eater and frequent water changes will therefore be required in order to keep the water quality up. The Mozambique tilapia is normally fairly peaceful as long at its young, but older specimens are known to become increasingly aggressive.
As mentioned above, the Mozambique tilapia is an omnivore species that will try most types of food. In the aquarium, they will eat virtually all kinds of prepared foods, including flakes, pellets and wafers. It is a good idea to supplement dry food with fresh vegetables such as zucchini and peas, and small servings of meaty live or frozen food, e.g. mosquito larvae and shrimps.
Conservation Status for Oreochromis Mossambicus
The Mozambique tilapia, Oreochromis mossambicus, is listed as Near Threatened (NT) on the IUCN Red List of Threatened Species. The Nile tilapia, Oreochromis niloticus, has entered the geographical range of Oreochromis mossambicus in the Zambezi and Limpopo systems with the help of anglers and fish farmers. This is a problem, since this two species readily mates with each other which leads to hybridization. According to IUCN, the Mozambique tilapia is likely to become locally extinct in those systems. Hybridization is not the only problem; competition can also pose a threat to the Mozambique tilapia.
Oreochromis Mossambicus as an Invasive Species
In some places, Oreochromis mossambicus have become an invasive species after being deliberately or accidentally introduced by man. It has for instance caused a sharp decline in the number of Striped mullets (Mugil cephalus) in Hawaii. The species is also suspected to be responsible for the problems experienced by the Desert pupfish (Cyprinodon macularius) in Salton Sea, California.
The Mozambique tilapia has been nominated by the IUCN Invasive Species Specialist Group (ISSG) as one of the species belonging to the group “100 of the World’s Worst Invasive Alien Species”.
The Mozambique tilapia is a highly adaptable species that can survive and even thrive in many different environments. This is naturally a good thing for the tilapia itself, but it is also what makes it such a risky introduction to non-native waters. It will for instance breed even in environments where food is scarce, and each female can rear several large broods each breeding season. The offspring can start breeding when they are no older than 8-9 months. The Mozambique tilapia is known to tolerate temperatures from 40 degrees F (4.4 degrees C) to 104 degrees F (40 degrees C), and they are also very tolerant when it comes to poor water quality, pollution and oxygen scarcity. They can survive in everything from lakes and major rivers to ditches to tiny ponds and can handle both fresh and brackish conditions. The Mozambique tilapia is also an opportunistic omnivore that will explore a wide range of different food source, from plankton and rooted plants to invertebrates and fish fry.
Blue tilapia (Oreochromis aureus) is also known as Israeli tilapia. It is an appreciate food fish and a common species in aquacultures worldwide. Blue tilapia is also sold as bait and aquarists keep it as a pet.
Habitat and geographical range
Oreochromis aureus is native to Cameroon, Chad, Egypt, Israel, Jordan, Mali, Niger, Nigeria, Saudi Arabia, and Senegal in tropical and subtropical African and the Middle East. It can for instance be encountered in the Jordan Valley, the Lower Nile, the Chad Basin, the Benue River, the middle and upper Niger, and the Senegal River.
Since Oreochromis aureus is such a popular food fish, it has been introduced by man to many other parts of the word through aquaponics, such as South East Asia and the Americas.
Oreochromis aureus lives in both freshwater and brackish environments, but it is most common in freshwater. In a few locations, it actually occurs in marine waters. Even though it hails from the tropics and subtropics it occurs at temperatures ranging from 8 to 30 degrees C (47 to 86 degrees F). It can tolerate a water temperature up to 41 degrees C (106 degrees F). A minimum temperature of 20-22 degrees C (68-72 degrees F) appears to be necessary for reproduction to occur.
Oreochromis aureus can adapt to many different types of habitats and occurs in open water as well as in densely grown environments. It lives in lakes, streams, ponds and impoundments.
Blue Tilapia Appearance
The largest scientifically measured Blue tilapia was 45.7 cm in length. The maximal published weight is 2,010 grams. The caudal fin of the Blue tilapia has broad bright red or pink distal margin. During the breeding period, the head of the male fish will change into a bright metallic blue shade and he will also display a vermilion coloration on the edge of his dorsal fin and an intense pink coloration on the margin of his caudal fin. A breeding female fish will develop a pale orange color on the edges of her dorsal and caudal fins.
Blue Tilapia Behavior
Blue tilapias form schools. They can sometimes be territorial.
Blue Tilapia Feeding
Young Blue tilapias eat a varied diet while adult fish tend to be fairly strict herbivores. Young Blue tilapias are known to include plenty of copepods and cladocerans in their diet and they will also eat small invertebrates if they get a chance. Adult fish feed chiefly on phytoplankton and epiphytic algae, combined with zooplankton once in a while. Blue tilapia can occasionally eat small fish. Blue tilapia seems to adapt their diet to the surrounding environment, because research carried out in different bodies of water has yielded different results.
Blue Tilapia Reproduction
Just like many other African cichlids, the Blue tilapia is a maternal mouth brooder. The male will build a nest and defend the territory. If his displays are not enough to fend of intruders, he can engage in mouth fighting. During spawning, the female fish will release her eggs in the nest and the male will fertilize them there. After fertilization, the female fish will pick up the eggs and head for deeper waters. She will keep eggs, larvae and fry in her mouth until the fry are large enough to be released.
Female Blue tilapias will usually reach sexual maturity when they are around 10 cm long (almost 4 inches), but reports of smaller females with ripe ovaries do exist.
As mentioned above, Blue tilapia seems to require a minimum temperature of 20-22 degrees C (68-72 degrees F) to breed. The species can reproduce both in fresh and brackish waters.
Conservation status for Oreochromis aureus
Oreochromis aureus has not been evaluated for the IUCN Red List of Threatened Species.
Oreochromis aureus as an invasive species
Blue tilapia that is introduced to non-native waters can be become a problematic invasive species. Compared to many other tropical fish species, it is fairly cold resistant and can therefore survive even in warm temperate environments. Studies indicate that the fish is more cold tolerant in waters with low salinity (5 ppt) than in freshwater. It should however be noted that Blue tilapia seems to require a minimum temperature of 20-22 degrees C (68-72 degrees F) to breed.
The Nile tilapia (Oreochromis niloticus) is an African cichlid native to Burkina Faso, Cameroon, Chad, Cote d’Ivoire, Egypt, Gambia, Ghana, Guinea, Liberia, Mali, Niger, Nigeria, Senegal, Sierra Leone, Sudan, Togo and Uganda. Nile tilapia is an important food fish that has been introduced to many different parts of the world by man and through aquaponics. It can today be found on all continents except Antarctica. In several countries, Nile tilapia has become a problematic invasive species after its introduction.
Subspecies of Nile tilapia
* Oreochromis niloticus baringoensis (Baringo tilapia)
* Oreochromis niloticus cancellatus
* Oreochromis niloticus eduardianus
* Oreochromis niloticus filoa
* Oreochromis niloticus niloticus
* Oreochromis niloticus sugutae
* Oreochromis niloticus tana
* Oreochromis niloticus vulcani
The two forms of tilapia referred to as Oreochromis “Nyabikere” and Oreochromis “Kabagole” are also suspected to be variants of Oreochromis niloticus.
The largest scientifically measured Nile tilapia was 60 cm (almost 24 inches) in length. The body of the fish is adorned with regular vertical stripes throughout the depth of the caudal fin. The caudal fin sports vertical bars. The dorsal fin margin is black or grey.
Nile tilapia inhabits a lot of different waters, from lakes and rivers to irrigation channels and sewage canals. It is considered a freshwater species but will tolerate brackish conditions as well. In the wild, it is typically found in waters where the temperature stays in the 13.5-33 °C (56-91 °F) range. The extended temperature range for this species is however 8-42 °C (47-108 °F). Nile tilapia is principally a day active fish that feeds chiefly on phytoplankton and benthic algae. It can also eat plants and have been introduced to ponds to reduce the amount of aquatic weed.
Just like many other African cichlids, the Nile tilapia is a mouthbrooding species where the female fish will keep egg, larvae and fry protected inside her mouth until the fry is large enough to be released.
Nile tilapia is a popular species for aquacultures, but using the wild type is no longer common since its dark coloured flesh is not very popular on the food market. Leucistic breeds have been develope that produces more lightly coloured meat. (Leucism is a condition characterized by reduced pigmentation in animals. It is similar to albinism but affects all type of skin pigment, not only melanin.) Hybrids containing genetic material from Nile tilapia are also important for the fish farming industry.
Cultivating Nile tilapia might sound like a typical 20th century endeavour, but the truth is that Nile tilapia was pond farmed in Ancient Egypt. The Egyptians called the fish ?n.t and it is represented by hieroglyph K1 on Gardiner’s Sign List. (Gardiner’s Sign List is a list of common Egyptian hieroglyphs compiled by Sir Alan Gardiner.) When used as a logogram, the hieroglyph simply meant Nile tilapia. When used as a determinative (ideogram), it signified both Nile tilapia and/or flathead mullets. Both fish types were of large commercial importance in Ancient Egypt. When used as part of a phonogram, the hieroglyph represented the sound ?n.
Nile tilapia has not been evaluated for the IUCN Red List of Threatened Species