The Bronze Corydoras is a peaceful, armoured catfish from South America and one of the most popular bottom-dwellers in the hobby.
Hardy and long-lived, it scours the substrate and brings constant gentle activity to the lower tank.
Despite a reputation as a clean-up crew, this is not a fish that survives on leftovers.
It is a genuine community species with real social and dietary needs that keepers must meet.
Housing
Keep a group in a tank of at least 75 litres (20 gallons) with a soft sand or smooth, rounded fine-gravel substrate to protect their delicate barbels.
Target 22-26C (72-79F), pH 6.0-7.5, in a fully cycled, well-oxygenated setup.
Provide shaded spots, plants, and driftwood for security.
They periodically dash to the surface to gulp air, so leave an air gap beneath a tight lid.
Sharp or coarse gravel erodes barbels and invites infection.
Diet
Bronze Corydoras are omnivores that should be fed directly, not left to scavenge.
Use sinking pellets, wafers, and tablets that reach the bottom, supplemented with frozen or live bloodworm, daphnia, and brine shrimp.
Feed once or twice daily, making sure enough food sinks past faster mid-water fish so the cories actually eat.
Slow starvation from relying on scraps is a common cause of decline; a proper sinking diet keeps them well-rounded and healthy.
Health
These catfish are robust but vulnerable to two husbandry faults: barbel erosion from sharp or dirty substrate, and red blotch or fin infections in poor water.
Keeping the substrate clean and parameters stable prevents most problems.
They are also sensitive to high nitrate and to salt and copper-based medications, so dose carefully.
Watch barbel length, breathing rate, and skin condition, and quarantine new fish.
With good care, individuals routinely live well beyond five years.
Temperament
Bronze Corydoras are sociable and peaceful, and are happiest and most active in a shoal of six or more of their own kind.
Kept singly or in pairs they become withdrawn, whereas a proper group displays its characteristic collective foraging and resting.
They coexist well with most calm community fish, including tetras, rasboras, dwarf cichlids, and peaceful barbs.
Their gentle nature means they should not be mixed with aggressive or large predatory tankmates.
A good fit for
Beginners wanting an active bottom-dweller
Peaceful community aquariums
Keepers using sand substrate
Long-term hobbyists (often 5-10 years)
Common mistakes to avoid
Keeping fewer than 6 (they are social)
Sharp gravel eroding their barbels
Assuming they survive on leftovers
Copper/salt medications they tolerate poorly
Is your enclosure big enough?
Minimum volume75 litres (20 US gallons)
CompanyCannot be kept alone. The minimum is 6, and the space above is for that group.
In a fish tank the patient is usually the water. Test before you treat — dosing a healthy tank for a disease it does not have makes things worse.
Go now
Any detectable ammonia or nitrite in a stocked tankLarge water change now with dechlorinated, temperature-matched water. Stop feeding. Test again in 12 hours. Both are directly toxic. How toxic the ammonia reading is depends on pH and temperature, so the same number can be harmless or lethal.
Now
Fish gasping at the surface, or crowding the filter outflowIncrease surface agitation immediately, then test the water. Either the oxygen has crashed or the gills are being chemically burned. Both are hours-scale problems.
Now
Sudden deaths, more than one fish in a dayTest ammonia, nitrite, nitrate and temperature before doing anything else. Do not add medication yet. Multiple simultaneous deaths point at the water or the equipment, not at a pathogen.
Now
Today
Flashing — repeatedly scraping against decor or substrateTest the water, then look closely for parasites. Irritation is either chemical or parasitic; the test tells you which before you medicate.
Today
White salt-grain spots over the body and finsBegin the appropriate treatment today and check the temperature. The parasite's life cycle is temperature-driven, and it multiplies with every cycle you wait.
Today
Soon
Clamped fins, hiding, or refusing food for more than two daysTest the water and review recent changes. Usually the earliest visible sign of a parameter drifting.
A few days
Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
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