Product Details

African Freshwater Dolphin – Mormyrus longirostris

The African Freshwater Dolphin is a fascinating and unusual African mormyrid with a long snout, intelligent behaviour and specialist sensory abilities. Correctly known as Mormyrus longirostris, this fish is best suited to very large, mature aquariums with soft substrate, subdued lighting and peaceful but robust tank mates. Although often sold as a juvenile, it is a large-growing specialist species and should only be kept by aquarists prepared for long-term predator-sized care.

Key Identification:

Common Name: African Freshwater Dolphin
Other Names: Freshwater Dolphin Fish, Eastern Bottlenose Mormyrid, Bottlenose Elephantfish, Elephantfish
Scientific Name: Mormyrus longirostris
Fish Type: Mormyrid / Elephantfish Relative
Water Type: Freshwater

Natural Range & Habitat:

Mormyrus longirostris is native to Africa, where it is recorded from large freshwater systems including the lower and middle Zambezi, lower Sabi and Ludi rivers, Luapula-Mweru-Bangweulu system, Ruvuma and Rufiji systems, and lakes including Malawi, Tanganyika and Rukwa.

In the wild, it favours quiet, deeper waters with soft muddy bottoms, caves, weed beds and sheltered areas. Aquarium care should reflect this with a spacious tank, soft substrate, dim lighting, shaded retreats, open swimming room and excellent water quality.

Appearance & Adult Size:

African Freshwater Dolphins have a long, streamlined body, extended snout and distinctive mormyrid profile. The body is usually grey, brown-grey, bronze or dark olive, with a subtle metallic sheen under aquarium lighting. The long snout and sensitive electrical navigation system help the fish search for food in low-light and muddy habitats.

This is a large species. Adults can potentially reach 60–75 cm, although aquarium specimens may vary depending on age, conditions and import size. Juveniles may look manageable when small, but adult size must be planned for from the beginning.

Aquarium Suitability:

This species is suitable only for very large, mature aquariums or specialist predator-style freshwater displays. It needs soft substrate, subdued lighting, calm areas, hiding cover and stable water quality. It should not be sold as a general community fish or a novelty addition for medium-sized tanks.

African Freshwater Dolphins are not suitable for small aquariums, bright bare tanks, sharp gravel, aggressive cichlid displays, nano communities, overcrowded setups or tanks with very small fish that may be eaten.

Recommended Aquarium Size:

A practical long-term minimum is 500 litres or larger for a juvenile growing on, with substantially larger aquariums required for adult fish. Adult housing should be planned around a long footprint of at least 200 cm, with larger custom aquariums preferred.

Footprint and swimming space are more important than height. This fish needs room to turn comfortably, explore the bottom and avoid constant contact with décor.

Water Conditions:

Temperature: 22–28°C
pH: 6.0–8.0
Hardness: Soft to moderately hard
Additional Notes: Stable, clean water is essential. Maintain excellent filtration, strong biological capacity, good oxygenation and regular partial water changes. Avoid sudden parameter changes, high nitrate, poor oxygen levels and harsh bright lighting.

Temperament & Tank Mates:

Aquarium Category: Predator

African Freshwater Dolphins are best treated as specialist predators. They are not usually aggressive in the same way as many large cichlids, but they can eat smaller fish and may be intolerant of unsuitable tank mates, especially in cramped conditions.

Suitable companions, if attempted, should be peaceful to moderately robust fish too large to be swallowed, calm enough not to harass the mormyrid, and able to live in similar water conditions. Possible examples include larger peaceful characins, larger catfish with care, calm bichirs with caution, and robust non-aggressive African species in very spacious aquariums.

Avoid small tetras, guppies, shrimp, small catfish, aggressive cichlids, fin-nippers, territorial bottom dwellers, electric fish competitors and any fish that may steal all food before the mormyrid can feed. Single-specimen care is often the safest long-term option.

Feeding:

African Freshwater Dolphins are specialist feeders and may be reluctant to take dry foods at first. Offer a varied diet of live and frozen meaty foods such as bloodworm, earthworms, river shrimp, prawns, mussel, chopped fish, blackworms, brineshrimp, mysis and insect larvae.

Some individuals may learn to accept sinking carnivore pellets or soft prepared foods, but this should not be relied upon immediately. Feed after lights dim if the fish is shy, and make sure food reaches the bottom. Avoid feeder fish, as they can introduce parasites, disease and poor nutrition.

Behaviour in the Aquarium:

This species is intelligent, cautious and often most active in low light. It may cruise slowly over the substrate, investigate caves and use its weak electric field to locate food and navigate. It can be shy when first introduced and may take time to settle.

African Freshwater Dolphins are known to form shoals in the wild, but aquarium group keeping is difficult because of their adult size and specialised requirements. In most home aquariums, they are best kept singly unless a very large specialist system is available.

Care Notes:

Add African Freshwater Dolphins only to a mature, fully cycled aquarium. Provide a soft sand substrate, dim lighting, shaded retreats and open swimming areas. Avoid sharp rocks, abrasive gravel and cramped layouts that may damage the snout or body.

Use care with medication, as mormyrids can be sensitive to some treatments, especially copper-based or harsh medications. They should be monitored closely during acclimation, feeding and water changes. This is an advanced fish for experienced aquarists, not a beginner community species.

Recommended For:

Experienced

Availability:

Occasional / Specialist import

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, body tone, snout length, fin shape, age and markings can occur between individual fish.