Rust Cory (Corydoras rabauti)

The juveniles and the adults look like two different fish. Young Corydoras rabauti carry a bold black zigzag band angling down the flank — striking, graphic, and completely unlike the adult. As they mature the pattern dissolves into a warm rust-orange body crossed by a single dark stripe running from behind the head to the tail. Buy them small and you get both fish for the price of one.

Beyond the colour change it is a compact, hardy, thoroughly likeable corydoras — smaller than a Bronze or Emerald, busy all day, and happiest in a group working across open sand. The rust tone is unusual in the genus and shows up far better against dark substrate than the silver and grey species most people end up with.

Care Snapshot

Scientific name	Corydoras rabauti
Also known as	Rust Cory, Rabaut's Cory, Dwarf Rusty Corydoras
Family	Callichthyidae — armoured catfishes
Origin	Tank-bred; native to the upper Amazon basin
Adult size	4–5 cm
Lifespan	5–8 years
Minimum tank	75 litres, minimum 60 cm length — floor area matters
Temperature	22–27 °C
pH	6.0–7.5
Hardness	2–15 dGH — tolerates hard water once acclimatised
Substrate	Fine smooth sand — non-negotiable
Diet	Omnivore — sinking foods, fed directly
Temperament	Peaceful, shoaling; keep 6+
Care level	Easy — given sand and proper feeding
Swimming zone	Bottom; surfaces periodically to gulp air

Setting Up For It

• Open sand, and plenty of it. Floor area is what counts for a bottom-dwelling shoal, not water volume. Leave broad clear stretches rather than carpeting the whole base with plants.
• Dark substrate brings out the rust. Over pale sand this species looks washed out; over dark sand the orange and the black stripe both read properly. Worth the choice on this one specifically.
• Keep the surface accessible. Corydoras breathe atmospheric air through the gut and must be able to reach the surface. Dashing up and back down is normal behaviour, not distress.
• Shade and shelter. Driftwood, broad-leaved plants and a dimmer light bring them out during the day. In a bright bare tank they hide until the lights go off.
• Siphon the sand at every water change. Food and waste settle exactly where these fish feed. Dirty substrate is the second route to barbel damage after sharp gravel.
• Keep six or more. Fewer than that and they stay hidden and inactive. A group is where the constant foraging behaviour comes from.

Tank Mates

Adult dwarf shrimp are generally safe alongside them, though shrimplets on open sand may be taken.

Feeding — They Are Not A Cleanup Crew

The most persistent myth about corydoras is that they live on leftovers. They do not. A group fed only on what drifts past the tetras will decline slowly over months, and because they are hardy fish it takes a long time to become obvious. Feed them deliberately, every day, with food that reaches the bottom.

From the AQA range, use a sinking wafer or small granule as the daily staple, with frozen bloodworm, brine shrimp or daphnia two or three times a week. Feed after the tank lights go off if faster fish are clearing everything first — these catfish are perfectly happy feeding in the dark.

Watch body condition from above. A healthy cory is rounded across the shoulders; a thinning one narrows noticeably behind the head.

Sexing & Breeding

Females are larger and distinctly broader when viewed from above, particularly when in condition. Males are smaller and slimmer with a more pointed outline. The difference is clear only in mature fish and is best judged looking down into the tank rather than through the glass.

Breeding follows the corydoras pattern and is well within reach at home. Condition the group heavily on live and frozen food, then trigger spawning with a large water change using cooler water, imitating the onset of the rains. The female carries eggs in a pouch formed by her pelvic fins and presses them onto glass, filter surfaces or broad leaves. Remove the eggs or the adults, as they will eat them. Fry hatch in three to five days and take baby brine shrimp and powdered food.

Keeping It In Indian Conditions

• Hard, alkaline tap water is fine for tank-bred stock. No RO or buffering needed. Room temperature across most of India sits inside the range for most of the year, so a heater is needed only for northern and hill-station winters.
• Watch the summer ceiling. This species runs a little cooler than the Bronze and Emerald corys and is less comfortable above 27 °C. Warm water also holds less oxygen, and these are bottom fish in the least oxygenated part of the tank. Increase surface agitation and run a fan across the water through April and May.
• Substrate is the thing to get right locally. Most Indian aquarium shops sell sharp crushed gravel, which is precisely what damages barbels. Fine river sand is cheap and widely available — rinse it thoroughly until the water runs clear.
• A large cool water change is a reliable spawning trigger, and in India the first heavy rains often set a group off on their own.