Taxonomy & naming
Scleromystax sp. CW198 has no formal description. The code CW198 comes from Ian Fuller's corydorasworld.com CW-number system, which tags identified-but-undescribed Corydoradinae much as the L-number system tags undescribed plecos. Scleromystax is a Corydoradinae genus of comparatively large, sexually dimorphic catfishes from the Atlantic-Forest drainages of south-eastern Brazil. A CW number is provisional — once the fish is described and given a valid name, the code is retired. For now there is no describing author, type series, or Catalog of Fishes entry.
Morphology
No formal morphology has been published for CW198. Trade sources put its adult length at roughly 3 in. It carries the usual Corydoradinae build — a short, deep body sheathed in two overlapping rows of bony plates, a downturned barbelled mouth for sifting the bottom, and locking dorsal and pectoral spines. Diagnostic counts and details wait on a scientific description, so any trade description should be read as provisional.
Habitat
Field data for CW198 come from exporters and aquarists, not surveys. Its recorded collection locality is near Joinville, Santa Catarina, Brazil. As a Corydoradinae it can be expected on soft-bottomed margins of Neotropical streams and rivers, but no measured habitat parameters — temperature, pH, flow — have been recorded for this form specifically.
Feeding
No diet study exists for CW198. Corydoradinae are bottom-grazing micro-omnivores that root through sand for small invertebrates, detritus, and anything edible that settles, and this form almost certainly does the same. In tanks, undescribed Scleromystax forms take the standard cory fare of sinking foods and small frozen or live invertebrates.
Mating
No courtship or spawning has been documented for CW198 specifically. Corydoradinae generally spawn in the classic T-position, the female holding a small clutch of eggs in her cupped pelvic fins while the male fertilises them; whether this form has been bred at all is simply not on record.
Breeding
There are no captive-breeding records for CW198. Clutch size, where the eggs are laid, and how the fry develop are all undocumented for this undescribed form. Keepers who spawn related Scleromystax forms lean on cool water changes as a trigger, but nothing specific has been reported here.
In the aquarium
Scleromystax sp. CW198 turns up only as the odd wild import and mainly interests keepers who track Corydoradinae by their codes. Ordinary Scleromystax care fits it — soft sand, clean well-oxygenated water, a shoal of six or more, and peaceful company. ScotCat suggests keeping it around 66–75 °F at pH 6.0–7.2; read those as care recommendations, not measured wild readings. It is a wild fish, not a line-bred strain, so what circulates under the code is collected stock.
Conservation
Scleromystax sp. CW198 has not been assessed by the IUCN Red List; as an undescribed form it has no formal status. With its range and numbers unrecorded, its real situation is unknown. Narrow-range Corydoradinae can be exposed to habitat change and collection pressure, which is reason enough to keep coded forms like this one on the radar.