Unusual Fish for the Aquarium
Species not Recommended for Novice Fishkeepers
Knife Fish, Reed Fish, Fire Eel and Leaf Fish are more difficult to keep in an aquarium but they can be a rewarding challenge to experienced aquarists.
Knife Fish
These fish belong to the order of Osteoglossiforms and Gymnotiformes. Knife Fish have a long, eel-like body which lacks a pelvic and dorsal fin but uses a long fin on their underside for swimming.
They have electric organs that generate a weak electric field in order to identify objects when navigating or looking for food. Knife Fish are mainly nocturnal so they become active in the evening to search for food which consists of crustaceans, insects and other fish.
A large aquarium is required for Knife Fish because they can grow quite big and need room to maneuver their long bodies. They avoid light so they need hiding places such as caves or hollow logs or large pipes. Smaller fish do not make good tank mates and Knife Fish can jump so a tight fitting aquarium lid is required. To mimic their nocturnal habits, feed them after the aquarium lights are turned off and remove uneaten food in the morning.
Reed Fish
Belonging to the Polypteridae or Bichir family, Reed Fish are primitive fish characterized by a snake-like body with a notched dorsal fin containing rays which look like many small fins. Reed Fish have air bladders which are rudimentary lungs that allow them to swim to the surface and breathe in oxygen. They are bottom dwellers and have poor vision so they rely on smell for finding food.
Reed fish require a large tank and preferably shallow with sand substrate. They need hiding places such as rock caves or hollow logs or pipes. In addition, they require an open area for swimming surrounded by plants. Use a tight fitting lid on the aquarium. Reed Fish are not territorial so a small number can be placed in a tank. They will get along with other species that are large in size.
Fire Eel
These fish belong to the Mastacembelidae family which is also known as the Spiny Eel family. Fire Eels are not true eels but they have elongated bodies like an eel. They are bottom dwellers and like to burrow into riverbeds with only their face exposed. When they are hunting for food, Fire Eels will swim anywhere.
Small Fire Eels can be kept in a medium size tank and will get along in a community aquarium. The larger fish need a bigger tank and the tank mates have to be of equal or larger size. It is recommended to keep only one in a tank with a tight fitting lid. Because they burrow, be prepared to have plants uprooted and decorations rearranged.
Leaf Fish
Belonging to the Polycentridae family, Leaf Fish have a large head that resembles a leaf and a tubular mouth resembling a leaf stalk. When they are hunting, they place their head down in order to resemble a leaf floating in water. Leaf Fish are able to change color according to their surroundings. They are known to catch prey much larger than their own bodies.
In an aquarium, Leaf Fish are middle dwellers and prefer to have lots of plants. They should not be kept with other species of fish because they are extremely predatory in nature.
