Two and a half to three inches, females clearly largest
An adult peppered corydoras reaches about two and a half to three inches long, and the sexes separate visibly at maturity: females grow larger, broader, and deeper-bodied, while males stay slimmer and a fraction shorter. The mottled grey-green peppering over a metallic body gives the species its name and its camouflage. Compared with the daintier panda corydoras, a peppered adult is a substantially more solid fish, and a group of them working the bottom of a tank has a weight and presence that surprises keepers who bought them as generic small catfish.
The corydoras that prefers its water cooler
Peppered corydoras come from cooler southern waters, and their adult care reflects it: they thrive at the lower end of the tropical range and stay active and long-lived in unheated or lightly heated setups where warmth-loving species would sulk. This makes them excellent companions for fish with similar temperature tastes and a poor match for tanks run hot for demanding tropical species. Within their comfort range they are famously forgiving fish, which is precisely why their signals get overlooked: a hardy three-inch catfish that stops foraging with its group is communicating something, even if the species has a reputation for enduring anything.
Pattern and build vary more than the label suggests
Peppered corydoras in shops are not all identical: the depth of the peppering, the green-gold sheen, and even adult build vary between individuals and bloodlines, and some fish sold under the name are close relatives with similar markings. For the keeper this hardly matters, because care is the same, but it explains why one group may finish nearer two and a half inches and another nearer three. Judge your own fish by condition rather than the ruler: a well-grown pepper is broad across the back when seen from above, with unbroken barbels and a pattern that stays dark and defined rather than fading to a washed-out grey.
Feeding a bigger bottom forager
A peppered adult can handle larger sinking foods than its smaller relatives, taking sinking wafers, granules, and frozen foods that would defeat a panda corydoras, but it still eats from the floor and still loses out when food never reaches it. Feed the bottom deliberately, after the midwater fish have had their fill, and scatter offerings so the group's smaller males feed alongside the dominant females. Their barbels do the finding, so a smooth, fine substrate keeps those sensory whiskers intact and the foraging confident across the whole footprint of the tank.
Groups, floors, and suitable companions
Like all corydoras, peppers are social to their core, resting flank to flank and foraging as a unit, so plan the group as deliberately as the tank itself. Their size and hardiness let them live with a wider range of mid-sized community fish than the tiny cory species can, provided nothing at floor level is territorial enough to drive them from cover. Keep a note of your group's sex mix and how the big females lead the foraging in the profile you maintain, because that social picture is what a new keeper most needs when adopting an established adult group. Should they move on, KinsLe's Transferrable Profiles let the peppered corydoras' profile go to that keeper with their history and routines intact.