Torrent catfish

Where they come from

Torrent catfish (Glyptothorax interspinalum) are built for whitewater. Think clear, cool, rocky hill streams in mainland Southeast Asia where the current never really lets up. They hug stones with that little adhesive pad on their chest, scooting around in the boundary layer while insect larvae tumble past. If you picture a stream you can hear before you see, you are on the right track.

Setting up their tank

Give them footprint and flow. Height is whatever, but length and current matter. For a small group, a 40 breeder or larger works well. A single fish can live in a 30-inch tank, but they show better behavior with company and room to pick favorite rocks.

• Flow: 15-25x tank volume per hour. Use a river-manifold or multiple powerheads pointed one direction to make a strong, laminar run.
• Oxygenation: heavy surface agitation or airstones. Aim for near 100% saturation; low O2 + warm water is a killer combo.
• Temperature: 20-24 C (68-75 F) most of the year. They handle down to ~18 C; try not to push above 26 C.
• Water: clean and stable. pH 6.8-7.6, soft to moderate hardness. Ammonia and nitrite 0; keep nitrate preferably under 10-20 ppm.
• Substrate and decor: smooth river stones, flat slate, rounded cobbles to grip. Leave open runs for current, with some slower pockets behind big rocks.
• Filtration: oversized canister or HOBs feeding the flow. Pre-filter sponges to catch grit so you are not blasting them with debris.
• Lid: tight-fitting. They will climb glass and ride current right into gaps.

Light can be moderate so algae and biofilm grow on the rocks, but keep heat under control. I rotate a few stones from a sunny shrimp tank into the catfish tank to seed them with good graze without cooking the water.

What to feed them

They pick at small invertebrates and biofilm in the wild. In a tank, think small, meaty foods that sink and ride the current. They are not big on hovering for flakes in midwater.

• Frozen and live: bloodworms, blackworms, daphnia, brine shrimp, chopped earthworm.
• Prepared: high-protein sinking pellets (nano size is easier to grab), Repashy gel blends pressed onto flat stones.
• Natural graze: algae and biofilm on smooth rocks. Rotate in algae-rocks from another tank if yours is too clean.

How they behave and who they get along with

Quiet, businesslike, and surprisingly quick. They spend a lot of time plastered to flat stones, then sprint to intercept drifting snacks. Mine were bolder at dusk and after the room settled down.

They will bicker over prime rocks, but it is mostly posturing if the tank has multiple high-flow perches. I like 3-6 together so no single fish gets bullied, plus you see more natural behavior.

• Good company: hillstream loaches (Sewellia, Gastromyzon), Garra species, river danios and Devario, Barilius, cool-water rasboras, white clouds, rhinogobius-type gobies that like flow.
• Mixed results: small shrimp (often become snacks), very boisterous loaches that compete at night.
• Avoid: warm-water fish that hate current (angels, bettas), long-finned varieties that get battered, large cichlids, and heavy nighttime bottom competitors.

Breeding tips

I have not seen a confirmed home spawning of G. interspinalum, and mine never bred. Closest I got was heightened chasing after a cool front and big water change. Most reports suggest seasonal cues and maybe egg deposition under stones in fast water.

• Set up a species-only tank with many flat stones forming crevices.
• Run very high flow with cooler temps (19-21 C) for a few weeks, feed heavily, then simulate monsoon with a series of large, slightly softer water changes.
• Use a grate or marbles under a stack of flats so eggs can fall out of reach if they do spawn.
• Dim lighting and minimal disturbance. Nighttime is when you are most likely to see activity.

Common problems to watch for

• Overheating and low oxygen: the big killer. If they are gulping at the surface or abandoning the flow, act fast with aeration and a cool water change.
• Starvation in busy communities: they lose food wars to faster midwater fish. Target feed or reduce competition.
• Scrapes and fungus: they wedge into tight spots. Keep rocks smooth and treat small fuzz early with clean water and gentle meds.
• Gill flukes and internal parasites: common on wild fish. Quarantine and deworm before adding to the display.
• Intake injuries: cover strainers; they can get pinned in strong suction.
• Shipping stress: they come in skinny. Do frequent small feeds, pristine water, and low stress for the first month.