Hoplisoma xinguense

Corydoras: from the Ancient Greek κόρυς (korus), meaning 'helmet', and δορά (dora), meaning 'skin, hide of an animal', in allusion to the rows of bony plates on the flanks of genus members.

xinguensis: named for the Rio Xingu, where the type specimens were collected, with the Latin suffix -ensis denoting place.[1]

Described from the upper Rio Xingu basin in Mato Grosso state, Brazil, and not reliably known from anywhere else.

Type locality is given as 'Suia Missú Creek, tributary of upper Rio Xingu near Posto Diauarum, about 11°15'S, 53°00'W, Mato Grosso State, Brazil'.

Museum collections also hold fish identified as this species from the lower Xingu in Pará and from the Tocantins and Tapajós drainages, but we've been unable to confirm those records, and several similar small spotted species occur in those rivers.[1][6]

Collected from small creeks flowing into the upper Xingu, several of them in forest, and from tributaries of the Culuene and Batovi, two of the rivers that join to form the Xingu.

A tank measuring 45 ∗ 38 ∗ 30 cm18 ∗ 15 ∗ 12 in is big enough for a group of this small species.

Use a substrate of fine sand so it can sift for food without damaging its barbels, and add smooth rocks and pieces of driftwood for cover. Some dense planting and a few floating plants to shade the tank are also appreciated.

Keep the water well oxygenated, with some movement at the surface. Like all corys it's sensitive to a dirty substrate and can lose its barbels in poor conditions, so keep the sand clean with regular water changes and don't use undergravel filtration.

Temperature: 22 – 26 °C72 – 79 °F

pH: 6.0 – 7.2

Hardness: 2 – 12 dGH[7]

An omnivore that forages on the bottom. It takes most sinking dried foods such as small pellets and tablets, along with small live and frozen foods such as bloodworm, Daphnia and Artemia.

Make sure enough food reaches the bottom for it. It won't thrive on what the fish above it leave behind.

Peaceful, and a good choice for a community of other small fishes such as small characins, pencilfish, rasboras and dwarf cichlids. It's one of the smaller corys, so avoid anything large or boisterous.

Keep it in a group, ideally of ten or more, as it's far more confident and active with plenty of its own kind around.

Females grow larger than males and are rounder and broader in the body, and the difference is easiest to see from above. Males tend to develop more pointed fin tips as they mature.[5]

It has been bred in the aquarium. Eric Bodrock spawned a group in April 1999 in a 38 litres10 US gal tank at pH 6.8 to 7.0 and 23 – 24.5 °C73 – 76 °F. He reported more than 120 eggs, and fry that grew very slowly.

Condition a group on live and frozen foods, ideally with two males to each female. Spawning in most corys is triggered by a large water change with slightly cooler water once the females are visibly full of eggs, repeated daily if nothing happens at first.

The male holds the female's barbels against his body with a pectoral fin, a posture known as the 'T-position'. In C. aeneus the female has been shown to drink the male's sperm. It passes quickly through her gut and is released over the eggs she holds in a pouch formed by her pelvic fins (Kohda et al., 1995). She then sticks the eggs to the glass or a plant leaf, a few at a time, and the process repeats.

The adults will eat the eggs, so either move them out after spawning or move the eggs to a separate container of the same water. The eggs are firm enough to roll gently off the glass with a finger. Remove any eggs that turn white with fungus. Once the fry have used up their yolk sacs they'll take microworm and newly hatched Artemia nauplii, and they do better over a thin layer of sand than in a bare container.[4][5]

Fish traded under the C-numbers C055, C105, C106, C107 and C108 have all been identified as this species. It's also sold as the dust cory.

Dias et al. (2024) split Corydoras into several genera using molecular and anatomical evidence, and placed this species in Hoplisoma. Its name there is Hoplisoma xinguense, with the ending changed to match the Latin grammar of the new genus name. The Catalog of Fishes and FishBase both follow them. This profile now follows Dias et al. (2024) in placing it in Hoplisoma.

Like all corys it can breathe air, taking oxygen through a modified, blood-rich section of its gut, so you'll see it dash to the surface now and then. More frequent trips than usual can be a sign that the water quality is falling.

The pectoral-fin spines are sharp, catch easily in a net and can give a painful jab, so take care when catching and handling it.[3][5][6]