Schmidt's hillstream catfish

Where they come from

Schmidt's hillstream catfish (Glyptothorax schmidti) comes from fast, rocky streams where the water stays cool, clear, and loaded with oxygen. Think mountain foothills - lots of current, slick stones, and not much soft plant growth. If you try to keep them like a typical "community catfish," they usually fade fast.

Setting up their tank

If you want a real shot with schmidti, build the tank around flow and oxygen first, and decoration second. I treat them more like a river fish than an aquarium fish.

• Tank size: 20+ gallons for a small group, but bigger is easier to stabilize (30-40 is comfortable).
• Temperature: aim cool to mid-range (around 20-24 C / 68-75 F). Long stretches warm tend to shorten their lifespan.
• Flow: strong, but not just "a filter output." Use a powerhead or wavemaker to create a river-like run along the bottom.
• Oxygenation: aggressive surface agitation helps a ton. If the surface looks like glass, fix that.
• Substrate: smooth gravel or sand with lots of rounded river stones. Skip sharp rock that can damage bellies and fins.
• Hiding and resting spots: wedge rocks to make crevices, add driftwood, and give them calm pockets behind rocks where they can park.
• Filtration: oversized, with prefilter sponges so they do not get pinned to an intake.

Water chemistry matters less than stability and cleanliness. Neutral-ish pH is fine in most cases, but ammonia/nitrite have to be zero and nitrate kept low. I also recommend a mature tank with biofilm on rocks - brand new sterile setups feel like a desert to them.

What to feed them

They are not algae grazers in the way a lot of hillstream fish are. In my tanks, schmidti did best on a meaty, varied diet, offered in ways that actually reaches the bottom in current.

• Staples: sinking carnivore pellets, small sinking wafers, and high-protein micro pellets that sink fast.
• Frozen foods: bloodworms (sparingly), blackworms, daphnia, brine shrimp, chopped mysis.
• Live foods (if you can): blackworms and small insect larvae get the best response.
• Occasional: Repashy-style gel foods pressed into crevices so it does not blow around.

Feed after lights dim a bit and watch them. If food is tumbling away in the flow, you are not really feeding the fish, you are feeding your filter. I like to drop food upstream of their favorite rocks so it lands where they sit, or use a feeding dish in a lower-flow pocket.

How they behave and who they get along with

They are generally peaceful, but they are not shy about claiming a rock. Expect little shoves and "parking spot" disputes, especially if you keep more than one and do not provide enough prime perches.

• Best kept: singly or in a small group with lots of rock territory (3-5 can work if the tank is built for it).
• Good tankmates: other cool-water, current-loving fish that will not harass them (small danios, some barbs, hillstream loaches that are not overly pushy).
• Avoid: slow fancy fish, long fins, warm-water species, and anything that likes still water (they will all be miserable together).
• Also avoid: aggressive bottom fish and big loaches that will outcompete them for food and resting spots.

Watch feeding time with tankmates. Schmidti can lose out to faster midwater fish unless you target-feed to the bottom. If you see them getting skinny even though you feed a lot, it is usually competition or the food is not reaching them.

Breeding tips

Breeding in home aquariums is uncommon. They are stream spawners, and a lot of the trigger is likely seasonal changes in flow, temperature, and food availability. I have seen courting behavior (more chasing and rock-claiming), but I have not personally raised fry from schmidti.

• If you want to try: keep a group, feed heavy with live/frozen foods for a few weeks, then do several larger cool-water changes to mimic rain.
• Increase flow during the "rain" period and keep oxygen high.
• Give them lots of small crevices between rounded stones - if eggs are laid, that is where they will be safest.
• Expect eggs/fry to be tiny and easily lost to filtration and tankmates.

Common problems to watch for

Most losses with this species trace back to the same few issues: not enough oxygen, not enough flow, or water that looks clean but is not stable.

• Rapid breathing, hanging near the surface: low oxygen, too warm, or not enough surface agitation.
• Constant hiding and not feeding: too much light/open space, bullying tankmates, or the current is all wrong (no resting zones).
• Sunken belly/weight loss: food not reaching them, internal parasites, or competition at feeding time.
• Frayed barbels/belly irritation: sharp substrate/rocks, dirty bottom, or bacterial issues.
• Sudden deaths after purchase: they ship poorly and do not love new tanks - acclimate slowly and put them in a mature setup.

My personal routine that kept them steady was simple: big biological filtration, lots of flow, weekly water changes, and feeding in a way that guarantees they actually eat. If you nail those basics, schmidti becomes a lot less mysterious, just still very picky.