Kryptos banjo catfish

Where they come from

Kryptos banjo catfish (Xyliphius kryptos) is one of those real oddball catfish from South America that shows up only rarely. They come from flowing river systems where the bottom is sand, leaf litter, and small bits of wood, and the water is usually clean and well-oxygenated.

The vibe to copy is: dim light, lots of bottom cover, and steady flow without blasting them around.

Setting up their tank

Think bottom-first. This fish lives its life on or in the substrate, and it is happiest when it can disappear. If you set the tank up like a typical "show" aquarium with bright lights and open gravel, you will just stress it out and hardly ever see it.

• Tank size: I would start at 20 gallons long for one, bigger if you want tankmates. Footprint matters more than height.
• Substrate: fine sand is the big one. They will scoot, wiggle, and sometimes half-bury themselves. Gravel can scrape them up.
• Cover: piles of leaf litter (Indian almond, oak, beech), small driftwood, and a few tight caves. Give them multiple hide options.
• Flow and oxygen: moderate flow plus strong surface agitation. A sponge filter plus a small powerhead works well.
• Lighting: dim. Floating plants or tannins help a lot.
• Water: stable, clean, and not swingy. Soft to moderate hardness is fine. Keep nitrates low. Temperature in the mid 70s F is a safe target.

What to feed them

These are bottom predators and scavengers, and they are not built to compete at feeding time. If you drop in flakes, the midwater fish will eat everything and your banjo will slowly waste away while looking "fine" for weeks.

• Staples: sinking carnivore pellets, small catfish wafers, and frozen foods (bloodworms, blackworms, chopped earthworm, daphnia, mysis).
• Best conditioning food: live blackworms if you can get them clean, or chopped nightcrawler/earthworm.
• How I feed: small portions, after dark, right onto the sand near their hide. I use feeding tongs or a turkey baster to place food.
• Frequency: smaller meals 4-6 nights a week beats a huge dump once in a while.

How they behave and who they get along with

Most of the time they are a living leaf. They sit still, bury a bit, and wait for food to come close. At night they cruise slowly and methodically.

They are generally peaceful, but anything that fits in their mouth can become food. Also, they do not appreciate boisterous tankmates bulldozing their hiding spots.

• Good tankmates: calm tetras, pencilfish, small peaceful cichlids that stay midwater, hatchetfish, gentle loricariids, and other non-predatory bottom fish that do not compete hard.
• Avoid: fin nippers, hyperactive barbs, aggressive cichlids, big predatory catfish, and tiny nano fish/shrimp you are attached to.
• With their own kind: usually fine if the tank has lots of hides. I still add them together and provide multiple tight shelters to reduce squabbles.

Breeding tips

Breeding Xyliphius kryptos in home aquariums is uncommon. They are secretive, likely seasonal spawners, and you rarely even see courtship behavior unless the tank is dialed in and the fish are mature.

If you want to take a swing at it, focus on conditioning and simulating a wet-season change rather than hunting for a magic trick.

• Start with a group if possible so you have both sexes (sexing is not straightforward).
• Condition for a month or two on heavier frozen/live foods, especially worms.
• Do a series of larger water changes with slightly cooler, well-oxygenated water and bump flow a bit for a few days.
• Provide tight caves and lots of leaf litter. If eggs happen, they will likely be tucked away where you cannot see them.
• If you suspect spawning, keep the tank calm and avoid deep gravel vacs that disturb the leaf layer.

Common problems to watch for

Most issues with this fish come down to three things: rough substrate, dirty water, or not getting enough food.

• Slow starvation: the fish hides, looks "normal" at a glance, then gradually gets thin. Fix with after-dark target feeding and less competitive tankmates.
• Barbel and belly abrasions: from gravel or sharp decor. Switch to fine sand and smooth wood/stone.
• Bacterial infections and fin rot: often tied to high organics and low oxygen. Improve filtration, increase water changes, and keep flow up without sandblasting them.
• Parasites from live foods: possible with wild-caught fish. Quarantine new arrivals and be picky about live food sources.
• Sudden deaths after big maintenance: can happen if you stir up a dirty substrate or change parameters too fast. Keep the leaf litter layer stable and do steadier, smaller changes if the tank is mature and "mucky."