I thought this excerpt from PlanetCatfish might interest you. It gives th manner of fertilization with the bronze Cory:
Keep in a shoal of at least 6 individuals - ideal first catfish for a beginner's community aquarium.
Breeding Easily accomplished with captive raised stock. Some colour varieties are more challenging than others. Given the presence of a suitably egg-laden female and a mature male or two, spawning can be triggered by a large, cool water change. Try changing 30-40% of the aquarium water (at 21°C) and bring the temperature down to 16°C. Do this slowly over an hour or two.The fish should respond by spawning in the classic 'T' formation method.
Here, using one of his pectoral fins, the male clamps the female to his side by her barbels and fertilizes a small batch of eggs held within the protective basket formed by her pelvic fins. The adhesive eggs are then placed on plants or aquarium walls and the process repeated. The eggs take 3-4 days to hatch. It is safe to leave well fed parents with the eggs, but some breeders prefer to remove the eggs, or indeed parents, to avoid any temptation of an easy snack.
For the first few days of their life, pre-soaked powdered flake food should be fed to the fry. After the first 3 or 4 days, newly hatched brineshrimp can also be sparingly used to bring on the fishes growth. As the fish grow more and more foods can be offered in line with the size of the developing juveniles. Adult colouration is reached in around nine weeks.
Another blog from PlanetCatfish on spawning C. paleatus (peppers):
It is considered that wild-caught C. paleatus are harder to breed than their tank-raised cousins. The latter commonly spawn in the community aquarium but a breeding tank of as little as 5 gallons will suffice and allow the fry to develop safely. A female and two males is the bare minimum, but more males can be added and some breeders actively recommend this. A period of ''fattening up'' achieved by feeding frozen or live foods followed by both a sharp drop of temperature and influx of fresh water should induce spawning.The female is shown here just prior to egg release. These eggs are held together in a clutch formed by the female's pelvic fins. How the actual fertilization of the eggs takes place is a matter of great debate amongst Corydoras breeders. Either the sperm is released in the water (possibly which the female wafts down the length of her body) and reaches the eggs OR the female ingests the sperm and somehow this passes through her body and is released over the eggs. This internal route is possibly a by-product of the mechanism that allows Corydoras to ''breathe'' air and dissolve it into the bloodstream in the lower gut. Detractors of the latter theory state that the female's mouth is clamped shut in gripping the male or is clamped to the body of the male by his pelvic fins! Whatever the route, it works. The female swims away and deftly ''lays'' the eggs, usually on the aquarium glass, but occasionally on broadleaf plants. Rearing is as for Corydoras similis
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