Marche's spiny eel

Where they come from

Marche's spiny eel is a Southeast Asian river fish. Think slow, warm waterways with sandy bottoms, leaf litter, and seasonal floods. They spend a lot of time buried with just the nose sticking out, picking off worms and small crustaceans at dusk and dawn.

Setting up their tank

• Tank size: 55 gallons for a single adult, 75+ if you want other bottom fish or more eels.
• Substrate: 2-3 inches of fine sand. They burrow daily. Skip sharp gravel.
• Cover: Tight lid, all gaps taped or stuffed with craft mesh. They are Olympic-level escape artists.
• Hides: Driftwood tangles, smooth rock piles, leaf litter, and a couple lengths of PVC or bamboo. Give options on both ends of the tank.
• Plants: Potted swords/crypts handle the digging. Floating plants help dim the light.
• Filtration and flow: Strong biofiltration with a gentle return. Add a pre-filter sponge on intakes so they do not rasp their noses.
• Water: 75-82 F (24-28 C), pH 6.5-7.5, soft to medium hardness. Weekly 30-40% water changes keep them happy.
• Lighting: On the low side. A dawn/dusk ramp helps them feel secure.

What to feed them

They are carnivores with a soft mouth. Think wiggly, meaty foods, offered near their hide so they do not have to compete.

• Staples: Live blackworms, chopped earthworms, frozen bloodworms, mysis, and chopped prawn.
• Treats: Small snails, daphnia, or chopped clam for variety.
• Training: Offer soft sinking carnivore pellets with tongs, mixed in with their favorite frozen. They learn, but it takes patience.
• Schedule: Small portions 4-5 nights a week. Skip days help avoid bloating.

How they behave and who they get along with

Shy at first, then curious once they figure out you are the food person. Mostly active at dusk and after lights out, but a settled eel will cruise in the afternoon too.

• Good neighbors: Medium, calm fish that do not hog the bottom, like rainbowfish, peaceful barbs, larger rasboras, gouramis, and mellow cichlids like severums.
• Use caution: Bottom bullies (aggressive cichlids, big loaches) and hyper-nippy fish. They stress eels and steal dinner.
• Not snacks-safe: Anything bite-sized (small tetras, nano rasboras, shrimp) may disappear at night.
• With other eels: Either keep one, or keep a roomy group of 3+ with lots of hides to spread out mild territorial squabbles.

Breeding tips

Very rarely done in home tanks. They are seasonal spawners that scatter eggs among plants or roots during flood periods. If you want to experiment, you will need space, patience, and a plan.

• Set up a large, quiet tank with dense plants and open sand lanes.
• Condition a small group with heavy live and frozen foods.
• Simulate seasons: several weeks of slightly cooler, softer water and big water changes, then shift warmer with abundant foods.
• Eggs are adhesive and the adults will snack on them. Pull eggs or move adults if you see spawning behavior.
• Fry need tiny live foods at first (paramecium/infusoria, then freshly hatched brine).

Common problems to watch for

• Jumping: Any gap is an exit. Check lids after every maintenance session.
• Rashed snout: Usually from rough substrate or intake strainers. Switch to fine sand and add a pre-filter sponge.
• Not eating: New eels often need lights-out feeding and live blackworms to get started. Once they settle, they accept frozen.
• Ich and parasites: Treat like a scaleless fish. Go gentle, add extra aeration, and avoid copper-based meds unless a vet directs you.
• Getting outcompeted: Feed after dark and use tongs. Add more hides so the eel feels safe coming out.
• Bacterial issues: They are prone to infections if the substrate is dirty. Vacuum lightly over the sand and keep up on water changes.