West African bottlenose mormyrid

Care at a glance

Overview

Another very large bottlenose elephantfish for pond-scale systems only. Keep it singly, as it will not tolerate its own kind, and choose tankmates with caution: large, calm fish that will not compete with it or nip at it. Give it a wide, deep bed of soft sand to plough with its snout, wood for cover, dim light, and rock-solid water quality. Feed meaty sinking foods such as earthworm, prawn, and mussel after dark. At around 80 cm it needs a tank of 700 liters at the very least, and realistically much more.

In the wild

Mormyrus rume is found across the Niger and Senegal basins and neighbouring Sahelian rivers of West Africa, foraging over soft bottoms in warm water. Recreate that with a deep sand bed, gentle current, subdued light, and a large footprint. Keep the water warm at 24-28 C and neutral to slightly alkaline, around pH 6.5-7.8, and very steady. Clean, heavily filtered water is essential for a fish of this size and sensitivity.

Good to know

This elephantfish of the family Mormyridae grows to around 80 cm and carries the down-swept bottlenose snout of the genus Mormyrus. Like all mormyrids it navigates by a weak electric field and has an unusually large brain for a fish. It is the western African counterpart of the Nile bottlenose and an important local food fish. Its breeding is not recorded in the aquarium.

Did you know

Mormyrids like this one have the largest brain-to-body ratio of any vertebrate, a shade higher than a human's, and their brains burn about 60 percent of the fish's oxygen, the most of any animal yet measured.

Common questions

Related species

• Eastern bottlenose mormyrid

  Mormyrus longirostris

  Freshwater

  29.5 in (75 cm)185 gal (700 L)75–82°F (24–28°C)
• Nile bottlenose mormyrid

  Mormyrus kannume

  Freshwater

  35.4 in (90 cm)185 gal (700 L)75–82°F (24–28°C)

• 

  Bebe mormyrid

  Hyperopisus bebe

  Freshwater

  20.1 in (51 cm)264 gal (1,000 L)73–82°F (23–28°C)

• 

  Elephant trunk mormyrid

  Campylomormyrus elephas

  Freshwater

  15.7 in (40 cm)119 gal (450 L)75–82°F (24–28°C)
• Painted mormyrid

  Hippopotamyrus pictus

  Freshwater

  11.8 in (30 cm)159 gal (600 L)73–82°F (23–28°C)
• Eel mormyrid

  Isichthys henryi

  Freshwater

  11.4 in (29 cm)79 gal (300 L)73–82°F (23–28°C)