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FishadvancedFreshwater

Fire Eel

Mastacembelus erythrotaenia

AnimaliaChordataActinopterygii

📍 Southeast Asia

Ask Finn

A large and visually stunning spiny eel from Southeast Asia, displaying a dark brown body with distinctive red-outlined yellow spots and stripes that become more vivid with age, reaching up to 36 inches. It is a burrowing fish requiring a deep, soft substrate and a very large tank (100+ gallons for adults), and will eat any fish small enough to fit in its mouth.

Size36"
Min Tank80g
semi-aggressive
Zonebottom

Care Guide

Diet

Fire eels are carnivorous and require a varied diet of high-protein foods including frozen bloodworms, brine shrimp, small fish, and quality sinking pellets. Feed 2-3 times weekly, adjusting portions based on tank size and individual appetite. Juveniles may require more frequent feeding than adults.

Behavior

Fire eels are nocturnal and spend much of the day burrowed in substrate, becoming more active at dusk and night. They are solitary and territorial, displaying semi-aggressive behavior toward tankmates, particularly smaller fish they may view as prey. They are generally peaceful toward larger, faster fish but will hunt anything small enough to swallow.

Breeding

Breeding fire eels in captivity is extremely rare and poorly documented. They require very large tanks (150+ gallons), specific water conditions, and significant maturity to attempt spawning. Most captive specimens are wild-caught, making successful breeding nearly impossible for hobbyists.

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

White spots on body and fins, flashing against substrate, labored breathing

Treatment

Raise temperature gradually to 28-29°C, use quality ich medication, perform 25% water changes every 2-3 days

Bacterial Infections

Symptoms

Torn fins, open sores, cloudy eyes, lethargy, loss of appetite

Treatment

Improve water quality, use broad-spectrum antibiotic medication, maintain pristine tank conditions

Parasitic Infections

Symptoms

Excessive mucus coating, scratching against substrate, weight loss, visible worms

Treatment

Use anti-parasitic medication, perform frequent water changes, quarantine affected individuals

Fin Rot

Symptoms

Frayed or deteriorating fins, discoloration at fin edges, progressive fin loss

Treatment

Improve water quality, perform daily 25% water changes, use fin rot medication if severe

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Water it likes

ph
6.5–7.5
ammonia
0 ppm
nitrate
<20 ppm
temperature
75–82°F (24–28°C)

Stats

Community tips0
Kept by0 hobbyists