Erpetoichthys calabaricus – Reedfish
The Reedfish (Erpetoichthys calabaricus) belongs to the family Polypteridae. It is a family of primitive fish. Fossils of Polypteridae have been found in rocks dating from 206-248 million years ago, the beginning of dinosaur development.
These ‘living fossils’ are found in much of Africa. Erpetoichthys calabaricus is the only species within the genus Erpetoichthys. They have a cylindrical elongated body, resembling an eel or snake. It is equipped with a scale armour. The pectoral fins are exactly where you would expect the legs of a lizard. The fish has up to 11 fin rays on the back, without fins.
The Reedfish was described by Smith as early as 1865. In the course of time, it has already seen many names. Synonyms are: Calamoichthys calabaricus, Herpetoichthys calabaricus, and Erpetoichthys robbianus.
The swim bladder has evolved into a primitive lung, which allows the fish to use air from the surface. Combined with the gills, they have two ways of breathing in order to survive in oxygen-poor water. Even if the oxygen level in the water is adequate, they will regularly swim to the surface for a breath of air. They will drown if it does not have access to atmospheric air.
Young specimens, just like salamanders, have clearly visible external gills. Although the ability to gasp for air gives the animal a perfect survival kit, it also introduces some problems. Since they have to surface at regular intervals, they are easy prey for snakes, birds and predatory fish. For this reason, they are perfectly camouflaged in body colour and shape, making them completely absorbed in their habitat from above. When hunted, they can completely burrow into the sand within seconds.
The skin is covered with a solid scale armor. The scales are triangular, with a hook at the end, and covered with a hard and tough material that also prevents water loss outside the water.
Erpetoichthys calabaricus has poor eyesight and largely follows scent trails to find food. For this, they are equipped with tubular nasal openings. Prey animals are slowly stalked and swallowed at close range. The Reedfish has two plate-like bone structures in the lower jaw that help it chew food.
A Reedfish can survive outside the water for several hours and in humid conditions for up to 2 days. The fish propels itself over land with the pectoral fins. Erpetoichthys calabaricus has been swimming in waters all over the continent for 70 million years. They are currently still found in West Africa, between Nigeria and the Congo area. This includes Congo, Angola, Nigeria, Cameroon, Guinea and Benin. They grow to a maximum length of 45 centimetres and live in still or lightly flowing water, which can also be brackish. They are nocturnal that mainly feed on annelids, crustaceans and insects.
The cautious character, the slow and graceful movements and the patient tracking by scent leave a pleasant and harmless impression. Appearances are deceiving: a hungry Reefdish can suddenly launch itself at high speed at prey.
Reedfish Sexual Dimorphism
The males of Erpetoichthys calabaricus have 12-14 fin rays, females have 9.
The curious appearance, healthy hunger and hardiness make the Reedfish a species that is easy to care for and for a very long period of time. In general, they are calm, who swim quite a lot and are just as often hidden. They are territorial but never bother other fish. However, smaller, especially more elongated, fish run a high risk of being swallowed. The Reedfish’s eyesight is poor. The prey is slowly stalked by a combination of chance and sense of smell and swallowed from close by. There are also never chases on the prey. However, if necessary, they can quickly propel themselves forward. They are a social species that feel more comfortable in a group.
They need an aquarium with open spaces combined with a lot of shelter in the form of plants, rocks or wood. Slightly dimmed light makes them feel more at ease and more active. They are powerful, muscular fish that like to hide and forage in the vegetation, so it is advisable to secure plants well. Caves, where they can hide, contribute to their well-being. The height of the waterline is not important, but the bottom surface is.
Younger Erpetoichthys calabaricus can be kept in a smaller aquarium from 80 centimetres. However, they grow quickly, after which a larger tank is of course necessary. Think of an aquarium with a minimum length of about 160 centimetres.
Cover the aquarium tightly and check that there are no cracks or openings in the hood: they are true escape artists. With sufficient strength in the body, they are able to push up cover plates and hoods. Furthermore, make sure they have the ability to draw air from the surface.
Suitable tankmates for Reedfish are primarily fish that do not fit in their mouths. These include:
Polypterus (preferably not too large)
Climbing Perches of the species Ctenopoma
African Butterfly Fish (Pantodon buchholzi)
Large Congo tetras
Ciclids of the genus Pelvichromis
Large Synodontis catfish
African Knifefish (Xenomystus nigri)
Do not keep Reedfish with aggressive fish species, such as territorial cichlids, Snakeheads (Channa) and fish species from the Labeo family. They are not resistant to aggression. The combination with catfish with a suction cup (for example Plecostomus) also does not work, since the catfish graze and destroy the armour of the Reedfish. Also, do not keep the fish with species that steal away food in a short time. Reedfish are reserved by nature and find food by their sense of smell. They are therefore not fast at food and starve in a food competition. They are furthermore fond of stable water conditions. They are also registered as brackish water fish. However, the salinity should never exceed 1.005.
P. de Pijper