Thick-Spine Spiny Eel

Mastacembelus aculeatus is a large and powerfully built spiny eel with noticeably strong and well-developed dorsal spines relative to its body size, giving it a more heavily armoured appearance than slender relatives. Found across South and Southeast Asia in rivers and floodplains, it is an active burrower that makes extensive use of deep sandy substrate.

Its robust build and tolerance for moderate water flow make it somewhat more adaptable to higher-flow aquariums than some of the more sluggish-water spiny eels. Strong filtration, deep fine sand, and a sealed lid are still essential. It grows large and requires a substantial aquarium with an appropriate bioload management strategy.

Earthworms and prawns are the preferred foods and reliably elicit a vigorous feeding response. It is peaceful toward large robust tankmates and can be combined with bichirs, large catfish, and robust cichlids. Its strong spine development means that prospective predators in a community setting will quickly learn to leave it alone, giving it a degree of natural protection.

Water: Soft to moderately hard, pH 6.5–7.5, temperature 24–28°C, GH 5–15, KH 2–8. Tank: Minimum 250 L, deep fine sand, robust decor, moderate flow tolerated, sealed lid. Feeding: Carnivore; earthworms, prawns, bloodworm, mussel, and sinking carnivore pellets. Breeding: Not documented in captivity. Compatibility: Peaceful with large robust fish; predatory toward small fish.