Fire Eel

Mastacembelus erythrotaenia is the crown jewel of the spiny eel hobby, a large and long-lived fish from Thailand, Myanmar, and surrounding countries whose bold red-orange markings on a jet-black body intensify dramatically as the fish matures. Juveniles arrive as dull brownish fish with faint red spots; adults become genuinely breathtaking display animals.

Fire eels are committed burrowers and demand a deep, fine-grained sandy substrate of at least 10 cm. A lid that is completely sealed is essential, as they are accomplished escape artists. They are nocturnal hunters that prefer dim lighting and will make use of PVC pipes, clay pots, or natural driftwood as daytime retreats.

Feeding progresses easily from live earthworms and frozen bloodworm to sinking carnivore pellets and prawns once the fish settles in. Tankmates must be too large to consume; they will readily eat small fish and invertebrates but are generally indifferent to similarly sized robust species.

Water: Soft to moderately hard, pH 6.5–7.5, temperature 24–28°C, GH 5–15, KH 2–8. Tank: Minimum 400 L, deep fine sand, dense hiding options, fully sealed lid is essential. Feeding: Carnivore; earthworms, frozen bloodworm, prawn, mussel, and sinking carnivore pellets. Breeding: Rarely bred in aquaria; egg scatterer among dense vegetation in soft warm water. Compatibility: Keep with large robust fish; will eat small fish and invertebrates.