Peacock Spiny Eel
Macrognathus siamensis
Peacock Spiny Eel (Macrognathus siamensis) — Advanced care, Aggressive, under Cichlid. Minimum tank in the app: 70 US gal min; aim for 75–82°F and pH 6.5–8.5. The Peacock Spiny Eel is ideal for experienced aquarists seeking a distinctly active bottom-dweller that engages with its environment.

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Africa / South America (varies)
- Africa
- South America
Regional colours match the stocking calculator’s origin map.
Peacock Spiny Eel Tank Setup
To accommodate the Peacock Spiny Eel, create a spacious layout with plenty of hiding places using rocks, driftwood, and caves. The substrate should be soft to protect its delicate skin, and moderate water flow helps mimic its natural habitat. Lighting should be subdued to encourage foraging behavior, helping the eel feel secure while still allowing visibility for observation.
What Do Peacock Spiny Eels Eat?
The Peacock Spiny Eel is an omnivorous feeder that thrives on a varied diet, but can be competitive during feeding times. Offering small, sinking pellets or live foods can stimulate natural hunting behaviors, yet it's essential to monitor that all tankmates receive adequate nutrition without being outcompeted.
Peacock Spiny Eel Tank Mates
Ideal tank mates are robust species that can fend for themselves, such as larger cichlids or fast-moving fish that occupy upper levels. Avoid long-finned or slow tankmates, as they may become targets for fin-nipping. Intraspecies interactions can be aggressive, so it's best to keep only one unless providing ample space and hiding options to diffuse tension.
Are Peacock 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 for this species, leading to poor water conditions that can exacerbate aggression and health issues. Another common error is introducing incompatible tankmates without considering size and behavior, leading to stress or predation.
Building a community? Run the full list through the stocking calculator before you add anything else.
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