Family: Callichthyidae
A peaceful omnivore callichthyidae from South America (from Trinidad to northern Argentina) — beginner-friendly.
Corydoras aeneus is a Callichthyidae. In the aquarium it stays peaceful. Plan on 5.2–7.5 cm of adult fish at 25–28 °C. Related profiles: Corydoras paleatus, Corydoras panda, Corydoras sterbai.
Very — they're the hardiest starter cory, content at 25–28 °C in neutral water. The one rule: they need company. Keep at least 6; groups under 4 stay stressed and disease-prone.
Normally it's grazing algae and leftovers. But if it keeps darting to the surface gulping air, that's low oxygen or gill trouble. Corys can gulp atmospheric air to supplement, but doing it constantly means water change and aeration time.
Fine sand or smooth small gravel (0.5–2 mm). They root through substrate with their barbels, and sharp or coarse material wears the snout and barbel bases raw — chronically melted barbels mean the substrate is wrong. Bare-bottom tanks essentially starve them.
Adults reach 5–7.5 cm — a mid-sized cory. With good care they live 5+ years, often 8–10. They're a commit-to-keep fish, not a disposable tank filler.
The classic T-position: the male angles under the female's head to fertilize, and she clamps the eggs between her pelvic fins to paste them on glass, leaves or wood. Remove the parents after spawning; eggs hatch in 3–5 days. A water change 2–3 °C cooler than the tank mimics the rainy season and often triggers it.
Ich (white spot disease) is the most common cory ailment, breaking out after temperature swings or unquarantined new arrivals. Raise to 28–30 °C to speed the parasite's cycle and treat with an ich remedy — about a week to cure. Corys are copper-sensitive, so halve copper-based doses.
Omnivores leaning carnivorous — sinking wafers, bloodworms and brine shrimp all work. They're weak competitors, so with greedy upper-tank fish you must feed sinking food deliberately. A concave belly tells you it's going hungry.
Nearly anything peaceful: tetras, guppies, discus, dwarf cichlids. Avoid large predators like oscars and arowanas, plus fin-nippers. Golden rule: any fry small enough to fit in its mouth may get eaten.
They're sensitive to temperature mismatch — new water should match the tank within ±1 °C and be dechlorinated. A gap over 3 °C commonly triggers ich. Weekly 25–33% changes are right; they tolerate dirty water better than fluctuation.
Bronze is the toughest and cheapest, growing largest — ideal first cory for beginners. Peppered is cold-tolerant and gentle; panda is adorable but dislikes heat. Start with bronze, then collect others once you've got the routine down.