Xingu spotted catfish

Where they come from

Xingu spotted catfish (Zungaropsis multimaculatus) come out of the Rio Xingu system in Brazil. Think warm, fast, super-oxygenated water running over rock and gravel, with lots of little cracks and pockets to hide in.

That background explains pretty much everything about them in captivity: they want current, clean water, and a safe place to wedge themselves where nothing can bother them.

Setting up their tank

This is an expert fish because the tank has to be built around its needs, not the other way around. If you like tweaking flow, dialing in filtration, and keeping water spotless, you will enjoy them. If you want a "set and forget" catfish, pick something else.

• Tank size: bigger is better. I would not bother under 75 gallons, and 125+ makes life easier if you want stable water and multiple hides.
• Layout: rockwork with lots of tight caves and crevices. Stack stones securely (or silicone them) because these fish push and wedge.
• Substrate: sand or smooth fine gravel. Skip sharp stuff - they spend time on the bottom and in cracks.
• Flow and oxygen: strong current and lots of surface agitation. A good canister plus powerheads works well, and an air stone is cheap insurance.
• Filtration: heavy. They are not huge pigs like some catfish, but they hate dirty water.
• Lighting: they do not care much, but dimmer light and shade from wood/rocks makes them show more natural behavior.

Water numbers matter less than stability and cleanliness, but aim for warm, soft-to-neutral freshwater. If your tap is hard and alkaline, you can still keep them, but you will have a much easier time if you keep nitrates low and keep up with water changes.

Feeding

They are bottom-oriented predators and scavengers. Mine learned the schedule fast and would cruise out at dusk once they felt safe. If you only feed flakes to the top, you will swear the catfish "does not eat" while it slowly loses weight.

• Staples: sinking carnivore pellets/wafers that hold together in flow.
• Frozen foods: bloodworms, mysis, chopped krill, chopped prawn, and quality mixed "carnivore" blends.
• Meaty fresh foods: small bits of shrimp or fish as an occasional treat, not a daily diet.
• Feeding time: evening works great. In bright tanks, feed after lights dim so they come out confidently.
• Portioning: small amounts, more often. Big dumps of food in a high-flow tank end up rotting in rockwork.

How they behave and who they get along with

They are not a "pet me" catfish. Most of the time they want to be wedged in a rock crack with just a bit of head showing. The payoff is watching them settle in, claim a hide, and start doing their rounds once they trust the tank.

Temperament is usually calm, but they are territorial about shelters. Two adults in a tight tank with one good cave will absolutely argue. Give them real estate and the drama drops a lot.

• Good tankmates: peaceful to semi-peaceful fish that like current (think streamy characins, robust tetras, some larger rasboras if the water is warm, and other current-loving species that will not pick at them).
• Avoid: fin nippers, aggressive cichlids that ram rockwork, and any fish small enough to become a snack at night.
• Bottom companions: be careful. Other cave-hogging bottom fish (some plecos, certain loaches) can turn it into a constant cave war.

Breeding tips

Breeding Zungaropsis in home aquariums is rare. In my experience and from what other keepers report, you should treat them as a species you keep for behavior and display, not a breeding project.

If you still want to try, the only realistic route is to keep a group in a large, river-style tank and let them pair up. Provide multiple deep caves, keep the water very clean, and mimic seasonal changes with heavier water changes and slightly cooler water for a short period, then warm it back up.

Common problems to watch for

Most issues I have seen with this fish come down to three things: not enough oxygen/flow, dirty water trapped in rockwork, and food competition. Fix those and they are surprisingly sturdy.

• Hiding nonstop and never eating: often stress from bright lights, lack of secure hides, or too much harassment from tankmates.
• Rapid breathing or hanging in the flow: usually low oxygen, high temperature without enough surface agitation, or clogged filtration.
• Sunken belly: they are getting outcompeted. Switch to night feeding and target-feed into their cave.
• Barbel wear or belly scrapes: rough substrate or sharp rocks. Smooth your hardscape and use sand or rounded gravel.
• Ich and other parasites after purchase: wild-caught fish can arrive stressed. Quarantine if you can, and do not rush them into a new tank.
• Mysterious ammonia/nitrate spikes: food and mulm trapped behind rock piles. You may need to redesign the scape so you can siphon and get flow behind the stones.

If you want a simple rule to keep them healthy: build the tank so you can clean it easily, and then actually clean it. River fish forgive a lot less than people think, but they reward you when you meet them where they are.