Half-banded Spiny Eel

Macrognathus circumcinctus

Half-banded Spiny Eel (Macrognathus circumcinctus) — Advanced care, Aggressive, under Other. Minimum tank in the app: 57 US gal min; aim for 75–81°F and pH 6.5–8. The Half-banded Spiny Eel appeals to aquarists seeking an intriguing predator for larger tanks.

Half-banded Spiny Eel (Macrognathus circumcinctus) in a planted freshwater aquarium
Care levelAdvanced
TemperamentAggressive
Min tank size57 US gal min
pH range6.5–8
Temperature75–81°F
Max size7.9 in (20.0 cm)
Captive lifespan8–12 years
SchoolingNo

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

Various

We don’t shade a region on this simplified map—your text may be Europe-only, worldwide, listed as “Various,” captive-only, or outside the five areas used in the stocking calculator. That tool still scores whether your fish come from similar parts of the world.

Regional colours match the stocking calculator’s origin map.

Half-banded Spiny Eel Tank Setup

Create a spacious layout with ample hiding spots using rocks and driftwood, while allowing free swimming space in the mid-to-bottom water column. Maintain moderate flow to mimic natural conditions, choose a dark substrate to enhance its coloration, and ensure lighting is subdued to encourage natural behaviors.

What Do Half-banded Spiny Eels Eat?

Half-banded Spiny Eels require a diet rich in protein, and they feed best during the evening or when the tank is dimly lit. Competition during feeding can be fierce if multiple aggressive eaters are present, so consider timing and placement to ensure all fish access food without stress.

Half-banded Spiny Eel Tank Mates

Ideal companions are larger, robust species that can withstand occasional aggression, such as certain cichlids or larger barbs. Small or slow-moving fish are at high risk, as well as delicate invertebrates. Intraspecies aggression can arise if multiple eels are introduced in confined spaces, so a solitary approach is best.

Are Half-banded Spiny Eels Good for Beginners?

This sits in the advanced range in the app. Strong filtration, stable chemistry, and reading up before purchase matter more than a catchy shop name. Aquarists often underestimate the space and filtration needs of this species, leading to poor water quality and stress. mixing with inappropriate tank mates can result in predation or increased aggression, compromising the tank's harmony.

Building a community? Run the full list through the stocking calculator before you add anything else.

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