no common name

Where they come from

Trichomycterus trefauti is a little stream catfish from Brazil. Think cool, fast, rock-and-gravel creeks with loads of oxygen, clear water, and plenty of places to wedge into. Seasonal rains hit those streams hard, so they deal with pulses of flow and food rather than a constant, gentle trickle.

Setting up their tank

Give them a long, mature stream-style tank. Length matters more than height. For a small group (3-6), I like 30-40 gallons with a 30-36 inch footprint. They hate stale water. Aim for brisk flow and lots of dissolved oxygen.

• Temp: 66-73 F (19-23 C). They handle brief dips cooler better than warm spikes.
• pH: 6.0-7.4. Soft to moderate hardness (1-8 dGH).
• Turnover: 8-12x per hour with a canister and/or powerhead. Point outlets along the length to make a current.
• Substrate: fine sand or smooth small gravel. Avoid sharp edges that chew up barbels.
• Hardscape: rounded cobbles, stacked slate, and wood. Build tight crevices and caves. Leave open runs for them to dash between hides.
• Filtration: strong biofilter with a prefilter sponge on intakes so they do not get sucked in.
• Lighting: on the dim side. Floating plants or shaded zones help.
• Water changes: 30-50% weekly. Fresh, cool water perks them up.

What to feed them

They are micro-predators that go for meaty, sinking foods. New arrivals almost always ignore dry pellets at first. Feed after lights out while they settle in.

• Live or frozen: blackworms, bloodworms, chopped earthworms, mosquito larvae, daphnia, baby brine (enriched), chopped shrimp.
• Prepared: soft sinking carnivore pellets or gel foods (Repashy-style) once they figure it out.
• Feeding rhythm: small portions 1-2x daily, with one fast day a week. They stuff themselves if you let them.

How they behave and who they get along with

Mostly crepuscular and nocturnal. By day they wedge under rocks and peep out; at night they cruise the bottom, pick through sand, and squabble a bit over the best hide. It is more bluffing than damage if you give them enough cover.

Tankmates need to like cool, fast water and not mind dim light. Think small, active midwater fish that will not bother the bottom. I have had the easiest time keeping them either in a species tank or with quick midwater schoolers that stay out of their way.

• Good: robust, current-loving midwater fish; peaceful whiptails; larger freshwater shrimp are risky but possible if well established.
• Questionable: very tiny fish or fry (they will get eaten), slow long-finned fish that struggle in flow, delicate shrimp.
• Group size: 3-6 spreads out the pecking order. Keep line-of-sight breaks so subdominant fish can disappear.

Breeding tips

These are rarely bred in home tanks. I have not raised a batch, but here is what has gotten me the closest: heavy conditioning on live foods, cooler water changes, and stacked slate/cobble piles with strong flow over the top and a calm pocket inside. They seem to prefer tight cavities.

• Set the season: a few weeks of generous feeding, then multiple 20-30% cool-water changes across a week.
• Provide options: flat stones leaned together, slate stacks, and pebble caves. Make several so fish can choose.
• Night watch: use a red flashlight. Courtship, if it happens, is brief and you will miss it under bright lights.
• If you find eggs: increase aeration right over the site and consider pulling the adults. A small egg tumbler with matching water works too.

Common problems to watch for

• Low oxygen: first sign is rapid gilling and hanging in the flow. Add air immediately and check for clogged intakes.
• Heat stress: they go downhill fast above mid-70s F. Keep a fan on the surface in summer and avoid placing the tank near windows.
• Barbel and mouth damage: caused by sharp substrate or rough netting. Use fine sand and catch them with a container, not a net.
• Internal parasites: many come in wild-caught and skinny. Quarantine, feed well, and deworm (levamisole followed by praziquantel) with extra aeration. Dose carefully with catfish-sensitive meds.
• Fungal tufts on scrapes (Saprolegnia): improve water quality and flow, then treat promptly. These fish do poorly in gunky water.
• Refusing prepared foods: keep offering tiny amounts after lights out while maintaining a solid live/frozen rotation. Most switch over in a few weeks.