Otopharynx tetrastigma
Otopharynx tetrastigma was first described by Günther in 1894. The fish belongs to the family Cichlidae. The genus name is derived from Greek: “ous” (οὖς) means “ear” and “pharynx” (φάρυγξ) means “pharynx.” The name possibly refers to a feature of the gills or throat structure of the fish. The species name tetrastigma also comes from Greek: “tetra” (τέτρα) means “four” and “stigma” (στιγμα) means “point” or “spot.” This refers to the four characteristic dark spots on the fish’s flanks.
Synonyms: Chromis tetrastigma, Cyrtocara tetrastigma, Haplochromis tetrastigma, Tilapia tetrastigma.
Appearance, Behavior and Lifespan
Otopharynx tetrastigma has an elongated, somewhat laterally flattened body. The head is light silvery brown, slightly darker on the back. Males may have a green/blue iridescent coloration on the head. The flanks are also pale silver, with three faint, brown spots. These spots are often not sharply defined. The abdomen is pale yellowish-silver. The lips of females are yellowish, in dominant males they can turn blue. Some specimens show a faint spot on the gill cover. The dorsal fin is yellowish with gray marbling on the back. The anal fin is yellowish with a faintly darker edge. The caudal fin is yellow with faint spots. The pelvic fins are yellow, turning to brown at the tips. The pectoral fins are translucent.
Males grow larger than females (males up to 17 cm, females up to 14 cm) and exhibit more intense coloration. Males have an iridescent turquoise color that transitions to blue on the head and body, with red iridescent colors on the body, red markings in the tail and dorsal fin. Females are silver with the same three-spot pattern as males, but less pronounced. Behavioral differences are mainly related to reproduction; males defend a spawning area and lure females. Juveniles resemble the females, with less pronounced colors.
Otopharynx tetrastigma is described as relatively peaceful, although they can exhibit territorial behavior, especially during reproduction. They are not shy and do not live in schools, but rather in small groups or as pairs. They are bottom dwellers that like to stay among Vallisneria and Ceratophyllum plants. In nature, they search for food by ingesting sand and separating the edible parts. When danger threatens, they dive into the sandy bottom.
Life expectancy: Life expectancy in the wild is unknown. In an aquarium, they can live 5 to 10 years.
Habitat and Ecology
Otopharynx tetrastigma is native to the southern part of Lake Malawi, in Malawi. They live specifically in the shallower waters of the lake, among Vallisneria and Ceratophyllum plants, and in the Shire River.
Their natural habitat consists of shallow, sandy areas with rock formations and dense vegetation of aquatic plants such as Vallisneria and Ceratophyllum. The bottom consists mainly of fine sand.
Lake Malawi has a tropical climate, with little variation in temperature throughout the year.
Diet
Diet in the wild: In their natural habitat in Lake Malawi, Otopharynx tetrastigma feeds by ingesting sand and separating the edible parts. They look for small crustaceans and insect larvae.
Diet in the aquarium: A varied diet can be offered in an aquarium, consisting of:
- Dry food such as granules, artemia and spirulina flakes.
- Frozen food such as mysis, krill, cyclops, shrimp mix, mussels, sprats and smelt.
It is important to give a varied diet to ensure that the fish gets all the nutrients it needs. It is also important not to overfeed, to maintain water quality.
The Aquarium
For a group of 5-7 adult Otopharynx tetrastigma, an aquarium of at least 300 liters (75 gallons) is recommended. Multiple pairs require an even larger aquarium, with the exact size depending on the number of pairs. An aquarium 150 cm in length is recommended as a minimum.
The aquarium should be set up to simulate the natural habitat of the fish. A fine sandy bottom is most suitable, since in nature they live in sandy areas and take up sand when searching for food. Rock formations and caves serve as hiding places, and a dense vegetation of Vallisneria or Ceratophyllum is appreciated by the fish.
Optimal water values are a pH of 7.5-8.5 (alkaline), a temperature of 22-28°C and a hardness of 12-16 dGH. Strong filtration and regular water changes are essential for good water quality.
Otopharynx tetrastigma is relatively peaceful, but may exhibit territorial behavior, especially during reproduction. Suitable co-inhabitants include other peaceful or semi-aggressive Lake Malawi cichlids, such as Aulonocara or Utaka species, and non-cichlids such as Synodontis catfish. Aggressive Mbuna cichlids should be avoided.
Breeding aquarium and conditioning
Breeding Otopharynx tetrastigma is relatively easy. A separate breeding aquarium is not strictly necessary, but may be more convenient for optimal results. A smaller aquarium (but still spacious enough for the pair ) with similar furnishings to the main aquarium would be suitable. The water quality should of course be optimal (pH 7.5-8.5, temperature 22-26°C, GH 12-16). The lighting need not be special.
To condition the fish for breeding, a varied diet is recommended, including dry food (granules, artemia, spirulina flakes), frozen food (mysis, krill, cyclops, shrimp mix, mussels, sprats, smelt). It is important to keep the fish well-fed and healthy.
The optimal ratio for a breeding group is 1 male to 2 or 3 females, or a multiple of this.
The Spawn
During spawning , the colors of males become more intense. Males show more intense turquoise and blue coloration on the head and body, with red iridescent colors on the body and red markings in the tail- and dorsal fin. Females generally remain less colorful.
The courtship ritual involves the male making a dimple in the sandy bottom, after which he tries to lure the female. With widely extended fins, he tries to impress the female with his colors and twitching movements. When the female is ready to spawn, she joins him in the shallow pit in the sand.
During mating, the fish rotate around each other. The female lays an egg, which is fertilized by the male in the same turn. The female then takes the fertilized egg into her mouth to incubate it (mouth brooding). This process repeats until all the eggs are laid. The number of eggs is variable, but can reach up to 60. Spawning can occur at any time of the day. Mouthbrooding females are very clearly identified by the thickened throat.
Raising the Young Fish
The eggs hatch after a few days. The female keeps the young fish in her maw for about 3 weeks after laying. They are still feeding on their yolk sac. The female eats little to nothing during this period. After three weeks, the female releases the young fish. The first food for the young consists of crushed flake food and small artemia.
In an aquarium with adult fish, the young fish are often eaten quickly. If you want to raise more young fish , catch the mouthbrooding female around day 17. Place her in a rearing aquarium with some sand on the bottom and a hiding place. After releasing the young fish, she will not eat her young immediately. You have plenty of time to catch the female after releasing the young fish and place them back in the main aquarium.
Conclusion
Otopharynx tetrastigma is a relatively peaceful and visually appealing cichlid from Lake Malawi, suitable for advanced beginners. Although generally easy to keep, they require a spacious aquarium (at least 150 cm in length) with a sandy bottom, rock formations, and sufficient plantings to simulate their natural habitat. A varied diet is important for their health and well-being.
A striking feature is their sand-hopping behavior when searching for food. The spawning process, in which the female incubates the eggs in her mouth (mouth brooding), is fascinating to observe. In general, keeping Otopharynx tetrastigma is a positive experience, provided their specific needs are met. Their relatively peaceful nature makes them suitable for a community Malawi aquarium with carefully selected co-inhabitants.
Video
Author
John de Lange
Copyright images
John de Lange
References
- Cleaver, Rachel M., Adrianus F. Konings, and Jay R. Stauffer, Jr. “Two new cave-dwelling cichlids of Lake Malawi, Africa.” Ichthyol. Explor. Freshwaters, vol. 20, no. 2, 2009, pp. 1–12
- Oliver, Michael K. “Six New Species of the Cichlid Genus Otopharynx from Lake Malaŵi (Teleostei: Cichlidae).” Bulletin of the Peabody Museum of Natural History, vol. 59, no. 2, 2018, pp. 1–42. – DOI:10.3374/014.059.0204
