Smudge-spot cory (Hoplisoma simile) care guide

Group
Freshwater fish
Other names
Smudge spot cory, Violet cory, Violetta cory, Corydoras similis
Family
Callichthyidae (armoured catfishes)
Origin
Rio Madeira basin in Brazil, including the Jamari, in small tributaries, creeks, pools and flooded forest.
Water
freshwater
Maximum size
3.8 cm
Temperature
21–27°C
pH
5.6–7
Hardness
Very soft to medium, 0–12 dGH
Minimum tank
41 litres
Care level
intermediate
Temperament
peaceful

Care

Keep at least six of this species together; in a proper group corys are far more confident and active. Formerly Corydoras similis, it is now Hoplisoma simile after the 2024 split of Corydoras (PlanetCatfish spells it Hoplisoma similis), but it is still usually sold as "Corydoras similis" and is often called the violet cory in shops. A tank of 45 × 30 × 30 cm (about 41 litres) is big enough for a small group. An Amazon-style set-up suits it: river sand, driftwood and a few dried leaves, although a well-kept planted tank works too. Use sand so they can sift without hurting their barbels, and keep the substrate clean. PlanetCatfish and Seriously Fish agree on about 21–27 °C and pH 5.6–7. Seriously Fish stresses that it is sensitive to worsening water quality, so change water regularly and do not let nitrate build up. PlanetCatfish describes it as a robust species once settled. Be careful with salt and medications, which corys tolerate poorly. Identification: look for the bluish-grey smudge at the base of the tail. PlanetCatfish describes it as the round-nosed counterpart of the long-snouted C. ourastigma, and the smudged tail marking separates it from other head-spotted species. C. caudimaculatus has a darker, sharper blotch and C. guapore is rounder and swims more in open water. Females are fuller (seen from above) and larger than males. Size: PlanetCatfish and FishBase give a maximum of 3.8 cm SL, smaller than the 6 cm quoted by Seriously Fish (the figure on our older page); the PlanetCatfish figure is used here. FishBase lists it as Least Concern on the IUCN Red List (assessed 2018). Ask the seller whether fish are wild-caught or captive-bred. Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=301); Seriously Fish (seriouslyfish.com/species/corydoras-similis/); FishBase (fishbase.se/summary/Corydoras-similis.html). Checked October 2026.

Diet

Omnivorous. Use flake and sinking tablets as the staple and add live and frozen foods such as whiteworm, bloodworm, Daphnia and brine shrimp (Tubifex only sparingly). Make sure food reaches the bottom; these fish should not be expected to live on leftovers.

Breeding

Females are rounder and larger than males, especially when full of eggs. PlanetCatfish reports success with two males to each female at about pH 7.2 and 24 °C, triggered by dropping the temperature by 5–6 °C with a cool water change; about 28 eggs were laid per spawning. Seriously Fish suggests a 45 × 30 × 30 cm breeding tank and large (50–70%) cooler water changes with extra oxygenation, repeated if needed. The pair adopts the classic cory "T-position" and eggs are mostly placed on the glass. Move the eggs or the adults afterwards and add a little methylene blue to prevent fungus. Eggs hatch in 3–5 days; then feed microworm and newly hatched brine shrimp. The fry do better over a thin layer of sand than in a bare tank.

Compatibility and tank mates

PlanetCatfish calls it a perfect citizen and suggests other similar Corydoras, dwarf cichlids and tetras as companions. Rasboras, small gouramis and other peaceful catfish also suit. Avoid large or aggressive fish and anything that outcompetes it for food at the bottom.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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