Taquari banjo catfish

Where they come from

Ernstichthys taquari is one of those fish that feels like it was designed to disappear. They come from the Taquari River system in Brazil (upper Paraguay basin, Pantanal region). Think slow edges, leaf litter, fine sand, tangled roots - the kind of places where a fish can lay still and look like a bit of debris.

That background matters because this species is basically a stealth ambush catfish. If you build the tank around that idea, they settle in and you actually get to see them.

Setting up their tank

If you try to keep these on gravel with bright lights and a bare floor, they usually turn into a stressed, skinny mystery fish you never see. Give them sand, shade, and lots of places to wedge into, and they act like they own the place.

• Tank size: I would not do them in anything under 20 gallons, and 30+ is more relaxing if you want a small group
• Substrate: fine sand (they bury and scoot, and sharp gravel can beat up their belly and barbels)
• Hardscape: piles of leaf litter, small driftwood branches, root tangles, and a few tight caves
• Plants: floaters help a lot with lighting; sturdy rooted plants are fine if you protect the roots from digging
• Flow: gentle to moderate; they are not a river-blaster fish

Filtration is a balancing act: you want clean water, but you do not want a sandstorm. I like a sponge filter or a canister with the return aimed at glass/wood so the flow is broken up. Keep intakes covered - these guys will plaster themselves onto weird spots.

Water-wise, they are pretty forgiving inside a reasonable tropical range, but stability matters more than chasing a magic number. Mid 70s F to low 80s F, soft to medium water, and a calm, mature tank beats constant fiddling.

What to feed them

They are not algae eaters and they are not great at competing at the surface. Think meaty, sinking foods, fed after lights-out. If you feed the tank normally during the day, they can still starve because they never win the rush.

• Staples: sinking carnivore pellets and wafers that soften fairly quickly
• Frozen: bloodworms, blackworms, daphnia, mysis, chopped krill (small pieces)
• Live (if you do it safely): blackworms are hard to beat for getting new fish eating
• Occasional: chopped earthworm bits for larger individuals

Watch body shape more than enthusiasm. A healthy banjo is thick behind the head and along the belly. If the fish looks pinched or paper-flat, it is not getting enough food, even if you are feeding the tank.

How they behave and who they get along with

Most of the time they act like a leaf that sometimes blinks. They bury, they rest, then they do slow little repositioning moves that make you wonder how you missed them five minutes ago.

They are generally peaceful, but they are still predators in the "anything that fits in my mouth at 2 AM" sense. Tiny fish and baby shrimp can disappear. With decent-sized community fish, they are usually fine.

• Good tankmates: calm tetras, rasboras, pencilfish, hatchetfish, small peaceful cichlids, other mild bottom dwellers that do not bulldoze them
• Use caution: other secretive bottom predators (competition at night), aggressive cichlids, big loaches that constantly dig
• Avoid: fish small enough to be swallowed, fin-nippers that harass slow fish

Breeding tips

Breeding Ernstichthys taquari in home aquariums is not common, and they do not hand you obvious signs the way some catfish do. If you want to take a swing at it, focus on conditioning and seasonal cues rather than fancy tricks.

• Start with a small group if you can, since sexing is not straightforward
• Condition with heavy meaty feeding (small frequent meals) for a few weeks
• Do a "rainy season" routine: bigger water changes with slightly cooler, softer water and increased oxygenation
• Provide tight caves and thick leaf litter so they have secure spawning sites
• If you ever see eggs or fry, move tankmates out rather than trying to net banjos out of a leaf bed

Common problems to watch for

Most issues with this species come from three things: not eating enough, being kept too bright and exposed, or getting roughed up by the wrong substrate or tankmates. They are hardy in a stable setup, but they do not bounce back fast if you miss the early warning signs.

• Slow starvation: the fish looks thinner week by week even though you feed the tank (fix with night feeding and target feeding)
• Barbel/belly damage: often from sharp gravel or dirty substrate (switch to sand, keep the top layer clean, avoid dead zones)
• Stress hiding: constant hiding is normal, but frantic darting or pale blotchy color usually means too much light, too much flow, or harassment
• Infections after scrapes: they sit on the bottom, so minor wounds can turn into fungus/bacterial issues if water quality slips
• Poor acclimation: they do not love sudden parameter swings, especially pH and temperature changes

One last practical thing: if you think yours is "gone," check under the leaves and along the glass at night with a dim flashlight. I have had banjos that looked missing for days, then I spot the outline of a fish-shaped leaf and realize they have been fine the whole time.