Bronze Corydoras Care Guide: Tank Size, Diet & Tank Mates

Species Overview#

Bronze corydoras (Corydoras aeneus) are the catfish most fishkeepers meet first. They've earned that spot honestly — a peaceful, armored bottom-dweller that scoots around the substrate in tight little schools, shovels up leftover food, and shrugs off water parameter swings that would flatten more sensitive species. If you walk into a local fish store and ask the staff for a beginner-friendly cory, this is almost always the fish they point to.

The species has been in the hobby for decades and has been line-bred into several color variants, including the popular albino form. Wild and captive-bred bronze cories share the same care needs and the same easy-going temperament, which is why they remain a permanent fixture in community tanks worldwide.

Adult size

2.5–3 in (6–7.5 cm)

Lifespan

5–10 years

Min tank

20 gallons (school of 6+)

Temperament

Peaceful

Difficulty

Beginner

Diet

Omnivore (sinking)

Natural Habitat & Origin#

Bronze corydoras are native to a broad swath of South America — Trinidad, Venezuela, Colombia, the Guianas, and as far south as the La Plata basin in Argentina. They live in slow-moving rivers, floodplain lakes, and seasonal creeks where the water is soft, warm, and often tannin-stained from leaf litter. The substrate in those habitats is fine sand or silt, and the cories spend most of their time rooting through it for worms, insect larvae, and bits of organic matter.

They also have a quirk that sets them apart from most catfish: they breathe atmospheric air. Cories will dart to the surface, gulp a bubble, and shoot back down. This adaptation lets them survive in oxygen-poor floodplain water during the dry season, and it's perfectly normal behavior in your home aquarium.

Appearance & Size#

Adult bronze cories reach 2.5 to 3 inches, with females running slightly larger and broader than males. The standard form has an olive-bronze body with an iridescent green-to-copper sheen along the flanks that catches the light when they swim. The belly is pale, the fins are clear to lightly tinted, and a pair of short barbels frames the mouth.

The albino variant — sold widely under names like "albino cory" — is the same fish with a recessive color mutation. Pink body, red eyes, identical care needs. Bronze and albino schools mix happily and will shoal together.

Lifespan & Hardiness#

A well-cared-for bronze cory will live 5 to 10 years in the home aquarium, with 7 to 8 years being typical. They reach this age because they tolerate the kind of mistakes beginner keepers make: a missed water change, a temperature drift, an accidentally late feeding. None of that is good practice, but bronze cories will forgive it where a more delicate fish would not.

Water Parameters & Tank Requirements#

The species is famously adaptable, but adaptable does not mean indestructible. Get the basics right and they will reward you with years of activity.

Ideal Water Conditions#

Bronze cories thrive across a wide range. Aim for the middle of these ranges and stability matters more than hitting an exact number.

Minimum Tank Size & Footprint#

A 20-gallon long is the practical minimum for a school of 6 bronze corydoras. The "long" matters — bronze cories are bottom-dwellers, so floor space counts more than tank height. A 20 long (30 by 12 inches of footprint) gives them room to forage and patrol the substrate. A 20 high (24 by 12) feels cramped to a cory school by comparison.

If you want to scale up, a 29 or 40 breeder is even better and lets you keep a school of 8 to 10 alongside a small community of mid-water fish.

Substrate & Filtration#

This is the single most important setup decision you'll make for cories.

For filtration, a sponge filter or a hang-on-back set to gentle flow works well. Bronze cories don't need river-grade current; they prefer calmer water with occasional slack zones where they can rest. If your filter return creates a strong current at one end of the tank, give them a sheltered spot at the other end with plants, driftwood, or rockwork to break the flow.

Diet & Feeding#

Bronze cories are omnivorous scavengers, but the "scavenger" label gets misused. They will not survive on tank leftovers alone — they need their own food, delivered to them.

Staple Foods#

Sinking pellets and wafers are the base of the diet. Hikari Sinking Wafers, Repashy bottom-feeder gel foods, and Bug Bites Bottom Feeder formula all work well. Drop the food in after the lights go out or just before, when the cories are most active and the mid-water fish have already eaten their fill at the surface.

Supplemental & Live Foods#

Rotate in frozen bloodworms, frozen or live daphnia, and the occasional blanched zucchini slice or cucumber round. The variety improves color, supports breeding condition, and keeps them engaged with feeding time. Two or three supplemental feedings per week is plenty.

Feeding Schedule & Competition#

Feed once or twice a day. The biggest feeding mistake new keepers make with cories is assuming the fish on top will leave food behind. They won't. Tetras, danios, and guppies are quick and will hoover up sinking pellets before they reach the bottom. Either feed after lights out, scatter food on the side of the tank opposite the schoolers, or use a feeding tube to deliver pellets directly to the substrate where the cories patrol.

Tank Mates & Compatibility#

Bronze cories are model community citizens. They ignore other fish, occupy the bottom layer that most species don't use, and never start fights.

Best Community Companions#

Pair them with peaceful mid-water fish: small tetras (neon, ember, rummynose), rasboras (harlequin, chili, lambchop), peaceful livebearers (guppies, platies, mollies), dwarf gouramis, honey gouramis, and otocinclus. They also live well with peaceful shrimp species and small snails — a bronze cory will not bother an adult cherry shrimp.

Species to Avoid#

Skip cichlids (most are too aggressive or territorial), large catfish like common plecos that will outcompete them at feeding time, and known fin-nippers like tiger barbs that may harass slow-moving bottom fish. Anything large enough to view a 3-inch cory as a snack — Oscars, Jack Dempseys, predatory pikes — is also out.

Keeping Them in Schools#

Breeding Bronze Corydoras#

Bronze cories are one of the easier corydoras species to spawn at home, which is why captive-bred stock is so widely available and so affordable.

Sexing & Conditioning#

Females are noticeably broader and rounder than males when viewed from above, especially when they're carrying eggs. Males stay slimmer with a more torpedo-shaped profile. Condition a breeding group with two weeks of high-protein live and frozen foods — bloodworms, blackworms, and live daphnia work well — to bring the females into spawning condition.

Spawning Triggers & Egg Care#

The trigger that mimics the South American wet season is a 5 to 10°F cool water change. Lower the tank temperature with a 30 percent water change using cooler dechlorinated water, then let it slowly return to normal over the next day. A barometric pressure drop from a passing storm front often kicks off spawning on its own with no help from you.

During spawning, the male and female form the classic corydoras "T-position" — the male curves his body perpendicular to the female and releases sperm, which the female collects in her pelvic fins along with one or two eggs. She then swims to a clean, flat surface (aquarium glass, broad plant leaves, or a piece of slate) and deposits the fertilized eggs. A productive female can lay 100 to 300 eggs in a single spawn.

Move the eggs — or the adults — to a separate hatching container, because adult cories will eat their own eggs. Eggs hatch in 3 to 5 days. Feed fry baby brine shrimp and crushed pellets once they're free-swimming.

Common Health Issues#

Bronze cories are hardy, but two issues come up often enough to know about.

Barbel Erosion & Bacterial Infections#

Worn or rotted barbels are the classic sign of inappropriate substrate or chronically dirty sand. Catch it early by inspecting the mouth area during regular tank checks — barbels should be intact and roughly the same length on both sides. Treatment is environmental: switch to soft sand if you haven't already, vacuum the substrate weekly to keep detritus from accumulating, and treat any visible bacterial infection with a gentle antibacterial like API Melafix at the labeled dose. Severe cases may need a stronger antibiotic.

Ich & Sensitivity to Salt and Medications#

Cories aren't truly scaleless, but they have small, plate-like scutes rather than overlapping scales, and they share the medication sensitivity of true scaleless fish. If you treat for ich (Ichthyophthirius multifiliis) — the white-spot parasite — use half the labeled dose of any copper-based or formalin-based product, and avoid aquarium salt as a primary treatment. Heat-based ich treatment (raising the tank to 86°F for two weeks) is the safest approach for a cory tank, provided your other species can tolerate the temperature.

Where to Buy & What to Look For#

Bronze cories are stocked by virtually every fish store, from chain pet shops to specialist LFSs. Quality varies. A healthy bronze cory should look like the description below.

Healthy Specimen Checklist#

Watch the fish in the store tank for at least a few minutes before you commit. A bronze cory that's foraging actively and breathing at a steady rate (not gulping) is in good shape. Ask the staff to feed the school while you watch — a healthy cory eats immediately.

Albino vs. Standard Bronze#

Albino corydoras are the same species with a color mutation. Care is identical. Big-box pet chains often stock albinos heavily because they sell well visually, while specialty LFSs may carry both forms or rotate based on what their wholesalers ship. If you want a particular form, call ahead.

For more on choosing a healthy starter freshwater stock list, see our freshwater fish overview and the 20-gallon tank stocking guide. If you're set on the albino color form, the dedicated albino corydoras care guide covers it specifically. For a smaller cory species, take a look at the pygmy corydoras guide — they're a 1-inch species suitable for nano tanks. For a popular striking variant, the panda corydoras guide walks through that species' slightly cooler temperature preferences.

Quick Reference#

• Tank size: 20-gallon long minimum for a school of 6
• Temperature: 72–79°F
• pH: 6.0–7.5
• Hardness: 2–12 dGH
• Group size: 6 minimum, 8–10 ideal
• Substrate: Soft sand only — no sharp gravel
• Diet: Sinking pellets and wafers as staple, frozen bloodworms and daphnia 2–3x weekly
• Tank mates: Small tetras, rasboras, peaceful livebearers, dwarf gouramis, shrimp
• Avoid: Cichlids, large catfish, fin-nippers, sharp substrate
• Lifespan: 5–10 years
• Difficulty: Beginner