Fairy Cory

About

The fairy cory is a pale, finely spotted catfish from two rivers in the upper Amazon, and it lands on the shelf beside every other spotted cory, where 'julii' is the trade's default label. Seriously Fish is blunt about that label on its own julii profile: many of the fish traded as Corydoras julii are not julii at all, but the similar-looking congener C. trilineatus. The name is the identification key: atropersonatus is Latin for 'black-masked', from ater 'black' and personatus 'masked', and Seriously Fish attributes it directly to the markings on the head. So the question to ask over the glass is what the head is doing. On a fairy cory the dark pigment is gathered into a band across the eyes, over a body Corydoras World describes as 'clear white with fine black dots'. On Corydoras julii the head carries 'numerous small, distinct spots'; on the three-line cory it carries 'a series of vermiform markings' — squiggles, not a mask. Provenance helps too: Seriously Fish places julii in coastal rivers south of the Amazon delta in north-eastern Brazil and notes that ornamental collecting is more frequent in the upper Amazon, where trilineatus lives. The fairy cory comes from the Tigre and Nanay in Ecuador and northern Peru. Seriously Fish adds that the fish it actually gets confused with are not those two at all but C. sychri and the undescribed C. sp. C097 — and of those only C097 is a real problem, since C. sychri is 'a more elongate fish with a longer snout and quite easy to identify', while C097 'resembles C. atropersonatus more closely' and its 'dark spots on the body tend to be more well-defined and spaced out than in the other two'. At 45–50 mm standard length it is one of the smaller shop corys. The 2024 Corydoradinae revision moved it into the resurrected genus Hoplisoma, so FishBase, the Catalog of Fishes, Corydoras World and Wikipedia now write Hoplisoma atropersonatum while every shop label still says Corydoras atropersonatus.

Care

An easy cory once the two non-negotiables are met: a group and sand. Six minimum, more is better, over soft fine sand — Seriously Fish allows rounded gravel 'provided it's kept scrupulously clean', but grit wears the barbels off and a barbel-less cory cannot forage. 60 cm of floor, gentle flow, a lid, and a working band of 23–25 °C. The sources disagree on temperature and both are quotable: Seriously Fish gives 21–27 °C, FishBase 21–24 °C; if you keep it at the cooler end, 23–24 °C satisfies both. Water chemistry is forgiving — pH 5.0–7.0 and 36–179 ppm at Seriously Fish, pH 6.0–8.0 and 2–25 dH at FishBase — so ordinary soft to neutral tap water works. Company: small characins, rasboras, dwarf cichlids, other quiet catfish. Handle it into a container rather than out of the water, because the pectoral spines can pierce skin.

Diet

Omnivorous bottom forager. Sinking wafers and micro-pellets plus frozen or live bloodworm, Tubifex, daphnia and brine shrimp, fed to the substrate so it does not lose the meal to faster fish above.

Telling males from females

What works for this species, most reliable first.

• Width from aboveStrong · from about 8 months, once they are adult-sized

  Corydoras are sexed from directly above, never from the side. Look down at the group while they rest on the sand.

• Bristles and cheek spinesA hint only · from about a year

  Male plecos grow odontodes — spiny growths on the cheeks and along the leading pectoral rays. Bristlenose males additionally grow branching tentacles across the snout and over the top of the head.

Also in these lists

Similar species

Same category and the closest water parameters — if this species isn't quite it, start here.

Health

Disease guide entries relevant to this species — worth a read before you reach for medicine.

Sold in Lithuania

These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.

These links are unpaid: we get nothing for them and ask for nothing.

Frequently asked questions

What tank size does a Fairy Cory need?

A Fairy Cory needs an aquarium of at least 60 litres (15.9 US gallons) with a footprint at least 60 cm (23.6 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Fairy Cory need?

Fairy Cory does best at 21–27 °C (69.8–80.6 °F), pH 5–7.5 and a general hardness of 2–10 °dGH.

What group size does a Fairy Cory need?

Fairy Cory is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.

Is the Fairy Cory suitable for beginners?

Yes — Fairy Cory is one of the easier species to keep and forgives typical first-tank mistakes, as long as the aquarium is cycled and maintained.

Sources

• Seriously Fish — Corydoras atropersonatus (Fairy Cory)
• FishBase — Hoplisoma atropersonatum (Weitzman & Nijssen, 1970)
• Eschmeyer's Catalog of Fishes — Corydoras atropersonatus Weitzman & Nijssen 1970
• Corydoras World — Hoplisoma (lineage 9)
• Corydoras World — Corydoras atropersonatus, article by Kim Mathiasen
• Seriously Fish — Corydoras julii (Julii Cory)
• Wikipedia — Hoplisoma atropersonatum