The direct answer for a corydoras
Food made for other kinds of pets is not safe for a corydoras catfish to eat as part of its diet. A corydoras will nose at nearly anything edible that reaches the bottom, which makes it look like a fish that can handle leftovers, but willingness is not suitability. The corydoras mouth is small, downward-facing, and built for sucking up tiny invertebrates and soft particles from sand, not for tackling chunks made for mammals. A stray flake of another fish's food is one thing; deliberate feeding of a corydoras with dog, cat, or other pets' food is a risk with no nutritional upside.
The physical risks of mammal food in a cory tank
Dog and cat foods pose physical problems for a corydoras before nutrition even enters the question. Kibble pieces are large and hard, soften unevenly in water, and can present sharp or crumbly fragments to a fish that feeds by mouthing the substrate and has delicate barbels it uses to taste its way around. A corydoras worrying at an oversized lump can damage those whiskers, and damaged barbels make its future feeding harder. Rich mammal food also collapses into a fatty paste that works down into the sand where a corydoras group lives and breathes, degrading exactly the layer of the tank they occupy all day.
The nutritional mismatch for an armored omnivore
A corydoras is an omnivore with modest needs: a balanced sinking food with some protein, some plant matter, and nothing extreme. Dog and cat foods are energy-dense for warm-blooded animals, with fat and mineral balances that overload a small corydoras when fed repeatedly, and their size encourages one fish to gorge while the rest of the group gets paste and crumbs. Foods made for herbivorous pets sit at the other extreme and leave a corydoras short of the protein it needs. Even pleco wafers and generic bottom-feeder foods should be checked for size and balance rather than assumed right, because a corydoras group needs portions scaled to small mouths, not a large algae disc meant for a much bigger fish.
If a corydoras has already eaten some
If a corydoras has eaten a little food dropped in by mistake, lift out the remains, vacuum the patch of substrate where it landed, and watch the group at their next proper meal. A corydoras that feeds normally, keeps its barbels busy, and shoals with the others has likely come to no harm from a one-off taste. Withhold the next sinking meal if bellies look rounded and the fish are ignoring food, since the group needs time rather than more input. Check the sand carefully over the following days for uneaten paste, because fouled substrate is the lingering danger to a corydoras after a rich-food incident. Any corydoras that stops feeding, isolates itself, or shows worn or shortened barbels should prompt a call to a veterinarian familiar with fish.
One menu for the cory group, written down
Corydoras tanks are often community tanks, which means several foods already enter the water and confusion is easy. List the cory group's own sinking foods, the amount for the group, and the rule that no other pet's food goes in, and keep that list with the feeding routine. That protects the corydoras from the most common accident: a helper finishing the round of household pets by dropping the last of the dog's dinner into the tank. In KinsLe Care Teams, that approved-food list can live inside the corydoras feeding duty, so the group's menu stays theirs alone whoever is feeding that night.