Multifilis threadfin

Care at a glance

Overview

This threadfin is a peaceful, sociable fish that lives near the bottom of big, open tanks and is happier in a small group than alone. It reads its surroundings through long pectoral filaments that trail along the substrate, and these are delicate sensory organs rather than decoration, so keep the layout smooth and open. Use fine sand and rounded wood, avoid sharp rock, and treat tankmates with caution: pick calm, similarly sized fish that will not nip the filaments or bully it. Feed meaty sinking foods such as bloodworm, prawn, and small pieces of fish. This is a large, demanding fish that needs around 600 liters or more.

In the wild

The multifilis threadfin lives in large, turbid lowland rivers of Indochina, Sumatra, and Borneo, moving over sandy and muddy bottoms where visibility is poor. It uses its filaments to feel and taste for food in the murk, so it needs open floor space and soft substrate rather than a cluttered aquascape. Keep the water warm and clean at 24 to 29 C with a pH of 6.5 to 7.5.

Good to know

Polynemus multifilis belongs to Polynemidae, the threadfins, and grows to about 28 centimeters. Each pectoral fin is split into roughly fourteen long, free filaments that move independently, giving the fish a bank of trailing sensors it uses to find food. Breeding is of moderate difficulty and little documented in aquaria, as this is a large river fish rarely spawned in captivity.

Did you know

It feels its way along the riverbed with a fan of thread-like fin rays, tasting and touching the mud for hidden food. The filaments work like extra fingers, letting it hunt in water too murky to see through.

Common questions

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