Hoplisoma leucomelas

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.

leucomelas:

Type locality is 'Yarinacocha, cutoff lake at right bank of Río Pacaya, near Sarayacu, about 5°15'S, 74°15'W, Upper Amazon, Peru'.

Mainly inhabits blackwater rivers and tributaries. The water in these biotopes is often stained brown with tannins and other chemicals released from decaying organic material, and is very acidic as a result. Hoplisoma leucomelas can be found schooling in very large numbers over soft, often muddy substrates.

Minimum base dimensi0ns of 90 ∗ 30 cm36 ∗ 12 in or equivalent are recommended.

Ideally use a substrate of fine sand, although rounded gravel is an acceptable alternative provided it’s kept scrupulously clean.

Other décor is largely down to personal choice, but some cover should be provided to give the fish security.

Corydoras spp. are foraging omnivores, and most will accept sinking dried foods as well as small live and frozen varieties such as chironomid larvae (bloodworm), Tubifex, etc.

Feeding a varied diet will ensure the fish are in optimum condition.

Under no circumstances should they be expected to survive on 'left-overs' from other inhabitants of the aquarium or relied on to 'clean' the aquarium.

Peaceful and gregarious. Should be maintained in a group of at least 4-6 individuals.

Females tend to grow larger, and sexually mature individuals are noticeably broader and deeper-bodied than males.

Can be bred in a similar fashion to many other Corydoras species.

Use a ratio of two or more males per female if possible, and when the females are visibly full of eggs perform a large (50-70%) water change with cooler water, and increase oxygenation and flow in the tank. Repeat this daily until the fish spawn.

Eggs may be deposited on the aquarium glass, among fine-leaved vegetation or within sunken spawning mops, with the latter particularly recommended since they facilitate easy removal of eggs.

Once spawning is complete either adults or eggs should be removed; the latter can usually be rolled gently up the glass with a finger. The new container should contain the same water as the spawning tank and be similarly well-oxygenated.

Most breeders add a few drops of methylene blue, or an alder cone or two at this point in order to prevent the eggs developing fungus.

Incubation is normally 3-4 days and once the fry have fully-absorbed their yolk sacs they are able to accept small live foods such as microworm, Artemia nauplii, etc.

They are not the easiest to raise, requiring excellent water quality, but seem less susceptible to ailments when maintained over a thin layer of sand rather than in a bare arrangement.

This species is one of the most abundant corys in its natural waters. It's caught and exported in huge numbers for the trade, often being shipped in consignments of "mixed Corydoras" or "spotted Corydoras" alongside similar looking, sympatric species such as Brochis agassizii, B. ambiacus, B. gomezi and occasionally Hoplisoma schwartzi. Unfortunately, most of these are easily confused and can be tricky to tell apart.

H. schwartzi is the most easily distinguished, as it's the only one to possess a creamy-white leading ray to the dorsal fin. H. leucomelas has an obvious dark band running through the eye, which is absent in both B. agassizii and B. ambiacus. In B. gomezi the dark dorsal marking is restricted to a spot in the upper part of the fin, whereas in H. leucomelas the marking extends into the upper body and is only present in the lower part of the dorsal fin.

Until 2024 this species was placed in Corydoras, then among the largest catfish genera with over 150 valid species. Dias et al. (2024) divided it into five genera and moved this species to Hoplisoma.

It is included in the family Callichthyidae, of which members are often referred to collectively as 'armoured' or 'mailed' catfishes group due to the presence of bony plates in place of scales on the body.

Their taxonomy can be confusing, and numerous undescribed species are also thought to exist. Fish of unconfirmed identification entering the aquarium hobby are therefore typically assigned a 'C' or 'CW' number for purposes of reference and organisation.

They are facultative air breathers and possess a modified, highly vascularised intestine which has evolved to facilitate uptake of atmospheric oxygen and aid survival in oxygen-deprived environments. In the aquarium you'll occasionally see them rising to the surface to take in gulps of air.

The stiffened pectoral-fin spines are capable of piercing human skin and a 'sting' can be very painful indeed, so care should be exercised when handling them.

It is thought that secretions from the axillary glands at the base of each spine may even be mildly toxic or venomous.