The Latin is the ID card: aurofrenatus means gold-bridled. Aurofrenatus Corydoras (Corydoras aurofrenatus) is a long-snouted catfish from the Paraguay River basin, with a yellowish bridle across the snout, not a short-faced Negro blaze and not a rusty Amazon pebble. Recent work treats Corydoras ellisae as the same species. If your shop still splits those names, you may be paying twice for one fish.

A long nose and a gold bridle

This is a Lineage-1, long-snouted Corydoras in the old sense: a conical, pointed snout built to poke deeper into sand than a panda’s face will go. Adults are around 5–6 cm, sometimes a little more in females. Ground colour runs pale yellow to yellowish-brown with a greenish-gold iridescence. Dark pigment concentrates above the eye like a sparse eyebrow; the namesake golden transverse band sits across the snout. The fish does not wear Adolfoi’s orange crown, schwartzi’s lined spots, or leopardus’s coarse blotches. The ventral surface is densely plated compared with some relatives — a character taxonomists care about and aquarists notice when the fish glides over glass.

Because the snout is long, this species is sometimes filed next to other “saddle-nose” corys. Compare carefully with other Río de la Plata long-snouts. CW005 in older lists is this animal. It is not a Brochis; dorsal-ray counts and snout details differ from the emerald tank-busters.

Paraguay basin, many substrates

Type material comes from Paraguay (Aguada near Arroyo Trementina, Aquidabán system). The range covers much of the Río Paraguay–Paraná world in Paraguay and adjacent Brazil (Mato Grosso, Mato Grosso do Sul), with records discussed for neighbouring countries. Field sites include sandy streams, clay-bottom creeks, turbid water, leaf heaps, and even stretches with rocks and trunks. That variety is why aurofrenatus is not a blackwater prisoner. It still wants clean water and a bed it can probe without filing the snout off.

This is not the upper Negro. It is not coastal Rio de Janeiro. It is interior South American river-plain water: tropical to warm-temperate depending on season, often turbid, often nearer neutral than a forest creek in São Gabriel.

Building for a snout, not a snoutless cartoon

Fine sand is non-negotiable because the fish will bury the front of the head while foraging. A long tank of 80 litres or more for a group of six-plus. Wood and leaf patches create foraging texture. Plants are welcome; Paraguay-basin tanks can be greener than Negro tanks. Moderate flow is acceptable; aurofrenatus is not a hillstream loach, but it is not a stagnant-bowl fish either. Lid on. Intakes covered. Skip angular gravel entirely — a long snout plus gravel is a medical photo waiting to happen.

Water without the tea ritual

Temperature 22–27°C. pH 6.0–7.6. Soft to moderately hard. Many Paraguay-basin fishes tolerate a wider mineral range than Cardinal companions would. If your tap is already reasonable, you may not need RO. If you keep them with Negro tetras, you are compromising someone. Ammonia at zero. Vacuum around the wood; the snout will go where the mulm is.

A bridled troop

Keep a group of the same long-snouts. Six is the minimum that behaves. They work the sand with a different motion than short-snouted corys: more probing, more “headstand” feeding. A single aurofrenatus looks like a lost pipefish made of armour. Mixed with short-snouted species they may still forage on the same floor, but the shoal language is not identical. If you want to see bridle-to-bridle grouping, buy aurofrenatus in number.

Concept Aquariums

Diet for a probe feeder

Omnivore. Sinking granules, frozen bloodworm, grindal, chopped earthworm, and crushed foods that sink into the sand — because that is where the mouth is. Surface flake is a tetra tax. They will miss food that only sits on a leaf in midwater. Feed in several sandy patches. They are not algae specialists.

Company on the Paraguay plain

Peaceful tetras that accept similar temperature, smaller livebearers if you like (this basin overlaps that world more than the Negro does), other corys, and quiet dwarf cichlids. Avoid large predatory fish. Hastatus pygmies can share a large planted Paraguay-style tank if you feed the pygmies properly; they use different levels. Do not add aurofrenatus to a mbuna tank because “catfish clean.”

Spawning a long-snout

Still a cory egg-scatterer: T-position, eggs on glass and décor, no care. Condition with meaty foods and a cooler water change. Long-snouts are sometimes reported as slightly more awkward in small breeding traps; a dedicated tank with sand and a sponge filter is kinder. Do not cross with random Lineage-1 fishes and call the babies aurofrenatus.

Snout health is the chapter that matters

Red, pitted snouts and stunted barbels are the species-specific disaster. Fix substrate and cleanliness. Ich and bacterial films happen as in other corys. Wild Paraguay fish may arrive thin after a long trip; feed them in peace before a community circus. Quarantine is still the adult move.

Why the bridle is worth a tank

Keep Corydoras aurofrenatus because you want a gold-bridled, long-snouted Paraguay-basin cory, and because you understand ellisae may be the same animal. Skip it if you wanted a short-faced spotted Purus fish or a midwater pygmy. The bridle is the name. The snout is the ecology. The sand is the tool. That combination does not belong in an Adolfoi article with the title swapped.

Ellisae, CW005, and the gold band you can actually see

Older books split C. ellisae as its own long-snout. Current work folds it into aurofrenatus. CW005 was the code while people argued. Your job is simpler: look for the bridle across the snout and the pointed head that goes into sand like a probe, not a shovel. Paraguay-basin streams can be clay, sand, or leaf heaps; the fish still wants a bed that will not grate that probe. If you only have gravel, you do not have a home for a gold-bridled cory, regardless of which synonym is on the invoice.

From above, a healthy group looks like pale gold cigars with dark eyebrows. From the side, you should see the snout working. If they only sit, the bed is wrong, the light is wrong, or there are not enough bridles in the tank. Six is the start of a probe team. One is a lost geological instrument.