Violet cory

Corydoras similis

Also known as Smudge-spot cory

FreshwaterFish

Violet cory (Corydoras similis) — Sergen Tuncer · CC BY 3.0

Care at a glance

Temperature: 70–81°F (21–27°C)
pH: 6.0–7.5
Adult size: 2.2 in (5.5 cm)
Minimum tank: 12 gal (45 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Bottom
Difficulty: Easy
Breeding: Medium
Rarity: Common
Origin: Rio Madeira basin, Brazil (South America)
Family: Callichthyidae

Overview

Keep them in a group of at least six, the more the better, in a tank of 45 liters or up. They are peaceful bottom dwellers that spend the day sifting sand for food, and a bigger group makes them bolder and more active. Hold the water at 21 to 27 C with a pH from 6 to 7.5, and stay on top of water quality since they are sensitive to dirty water and high nitrate, so keep nitrate under about 30 ppm and skip undergravel filtration. Feed sinking pellets, frozen foods like bloodworm and daphnia, and let them pick over the substrate. They are safe with shrimp and small peaceful fish, so avoid large or aggressive tankmates. Never release aquarium fish into local waterways, and check your area's rules before keeping them.

In the wild

Violet cories come from the Rio Madeira basin in Brazil, slow soft-water tributaries in the western Amazon. The bottom there is fine sand and leaf litter under driftwood and roots, which is exactly what they sift through for food. Give them a soft sand substrate they can dig their barbels into, since sharp or dirty gravel wears the barbels down and leads to infection. A planted tank of 45 liters or more with driftwood, roots, and some leaf litter suits them, kept at 21 to 27 C with a pH from 6 to 7.5.

Good to know

This is Corydoras similis, a small armored catfish in the family Callichthyidae, also sold as the Smudge Spot or False Julii cory. Kept adults usually reach about 5.5 cm. It is an egg scatterer with no parental care, and a healthy fish can live several years. Like other cories it can gulp air at the surface and pass it through the gut to take up oxygen.

Did you know

The smudge that gives them the Smudge Spot name, plus the broken dark pattern, is why they get confused with the julii cory in shops. The two look close as juveniles, but real Corydoras julii has fine separate spots on the head while similis carries more of a connected, marbled pattern as it grows.