African Freshwater Dolphin - Mormyrus longirostris

African Freshwater Dolphin (Mormyrus longirostris)

The African Freshwater Dolphin is a fascinating and unusual mormyrid from Africa, also known as the Eastern Bottlenose Mormyrid or Freshwater Dolphin Fish. It has a long, dolphin-like profile, an extended snout, intelligent behaviour and the ability to sense its surroundings using weak electrical signals. This is a specialist, large-growing freshwater fish best suited to experienced keepers with spacious aquariums, soft substrate, subdued lighting and carefully chosen tank mates.

Common Name:
African Freshwater Dolphin. Also commonly referred to as the Freshwater Dolphin Fish, Eastern Bottlenose Mormyrid or Bottlenose Mormyrid.

Scientific Name (Latin):
Mormyrus longirostris

Maximum Size:
Up to around 75 cm in the wild. In aquariums it is still a very large-growing species and should be planned for as a long-term monster fish rather than a standard community fish.

Water Type:
Freshwater

Origin / Natural Habitat:
Native to parts of eastern and southern Africa, including river and lake systems such as the Zambezi, Sabi, Luapula-Moero-Bangwelo system, Ruvuma, Rufiji, Lake Malawi, Lake Tanganyika and Lake Rukwa. In nature it favours quiet, deeper freshwater areas with soft muddy bottoms, caves, weed beds and sheltered areas.

Water Parameters:
Temperature: 24–28°C
pH Range: 6.5–7.5
Hardness: soft to moderately hard water

Temperament:
Semi-aggressive and specialist. It can be territorial, especially as it grows, and may be aggressive towards similar fish or other weakly electric species. It should not be kept with very small fish that may be eaten, or with overly aggressive tank mates that may damage its snout or stress it.

Diet:
Omnivorous with a strong preference for meaty foods. In the aquarium it should be offered a varied diet including bloodworm, earthworms, chopped prawn, mussel, small crustaceans, insect larvae, frozen foods and suitable sinking carnivore foods if accepted. Some individuals can be slow or selective feeders, especially when newly imported.

Minimum Tank Size:
A practical long-term recommendation is at least 800 litres, with a very large footprint and excellent filtration. Larger adult specimens may require even more space, especially if kept with other large fish.

Behaviour & Activity:
This is a bottom-to-mid level species that is often more active in subdued lighting or during quieter periods. It uses weak electrical signals to navigate, communicate and locate food, which makes it highly sensitive to its environment. It appreciates soft sand, smooth décor, caves, shaded areas and open floor space for movement. Avoid sharp rocks or abrasive substrate, as the snout can be damaged.

Aquarium Category:
Semi-Aggressive
This species is best kept with robust, peaceful-to-semi-aggressive fish that are too large to be eaten but not aggressive enough to bully or nip it. Suitable tank mates may include larger peaceful catfish, large characins, bigger barbs, larger bichirs and calm cichlids in very spacious aquariums. Avoid tiny community fish, fin nippers, aggressive cichlids, other mormyrids and electric fish.

Special Requirements or Care Notes:
This is a specialist mormyrid and should only be kept in a mature aquarium with stable water quality, strong filtration and low stress levels. It does best with subdued lighting, hiding areas and a soft sandy substrate. Avoid copper-based treatments unless absolutely necessary and used with extreme care, as mormyrids are often considered sensitive fish. Because it is a weakly electric species, it is best not mixed with other mormyrids unless the aquarium is exceptionally large and the keeper is experienced.

Suitable for:
Experienced fishkeepers

Availability:
Rare / occasional in trade

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.