Fresh Water Dolphin

fish description – Fresh Water Dolphin Care Guide ($Mormyrus\ longirostris$)

Category	Detail
Scientific Name	$Mormyrus\ longirostris$
Common Name	Fresh Water Dolphin, Bottle-Nosed Mormyrid, African Freshwater Dolphin
Origin	Rivers and swamps across Africa (Zambezi, Congo, etc.)
Adult Size	15–30 inches (38–75 cm) (Max size up to 30 inches, typically smaller in aquaria)
Temperament	Peaceful but territorial towards its own kind and small bottom-dwellers; mostly nocturnal
Lifespan	8–15 years
Care Level	Advanced (due to size, diet, and electrical organs)

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Appearance and Sexual Differences

 

• Short Description: A highly unique, eel-like fish with a silvery body and a distinctive, long, fleshy, downturned snout that gives it a “dolphin” look. It uses this snout and its electrical organs to root through the substrate for food in dark, murky water.
• Coloration: Silvery-grey to dark olive-brown. Coloration is typically subdued. Sexing is very difficult and usually requires internal examination or observing during breeding.
• Fins: Proportional fins, with a long dorsal fin.
• Behavior: Highly intelligent, curious, and nocturnal. It uses electroreception to sense its environment and communicate. It loves to burrow and root through soft substrate and requires ample hiding spots.

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Tank Requirements and Water Parameters

 

• Minimum Tank Size: 200 gallons (757 liters) is recommended for a single adult due to its potential size (up to 2.5 feet). The tank must be long and wide to provide ample swimming space.
• Schooling: Generally social but best kept singly in most home aquariums due to potential conspecific aggression as adults. If groups are kept, the tank must be massive (400+ gallons).
• Temperature: Tropical range: $75^\circ$–$82^\circ\text{F}\ (24^\circ$–$28^\circ\mathrm{C})$ (stability is vital). They can be sensitive to high temperatures where dissolved oxygen drops.
• pH Level: Slightly acidic to neutral water: 6.5 to 7.5 (tolerates 6.0–8.0). Requires pristine water quality and stable parameters. Strong filtration is needed, but water flow should be moderate.
• Aquascape: Requires a soft, deep sand substrate (essential for burrowing/foraging). Decorate with plenty of driftwood and caves to provide hiding spots for daytime use. Lighting should be dim or subdued; bright light will cause them to hide. Avoid metal décor or objects that could leach metals (toxic).

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Diet and Feeding

 

The Fresh Water Dolphin is a carnivore that feeds on benthic invertebrates and small vertebrates.

• Staple Diet: Consists of worms, insect larvae, and small crustaceans in the wild. This fish is notoriously picky and often refuses dry pellets or flakes unless trained aggressively.
• Supplementation: Must be fed a protein-rich diet of high-quality live or frozen foods: Bloodworms, Blackworms, White Worms, and chopped pieces of shrimp or fish fillet. Live food may be needed initially.
• Schedule: Feed 1–2 times daily, preferably in the evening or after lights out to match their nocturnal activity and ensure they get food without being out-competed.

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Compatibility

 

• Caution: Avoid all small fish that could be swallowed. Should not be housed with other electric fish (like Electric Catfish or Knifefish), as their electrical fields can interfere with each other. Avoid aggressive fish that might damage their snout/skin.
• Good Tank Mates: Peaceful, large fish that are not aggressive and occupy the mid-to-upper water column. Examples include Congo Tetras, Larger Barbs, Synodontis Catfish, Arowanas, and Large Gouramis.