Slate Cory
Hoplisoma concolor
Callichthyidae
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About
The slate cory is the plain one, and being plain is its whole problem. Every other cory on the shelf is sold on its pattern — the panda's eye patch, the sterbai's white spotting, the adolfoi's orange nape — and this fish has none: Seriously Fish separates it from its congeners by 'its uniformly greyish colour pattern, deep body (fitting 2.1-2.4 times in standard length), large eye (3.2-4.0 times in head length), having the pectoral fins completely surrounded by the coracoid, and relatively long dorsal-fin spine'. Those are proportions and bone, not markings, which is exactly why an unlabelled grey cory in a mixed shop tank tends to be sold as whatever it is standing next to. Two things do give it away without a ruler: it is bigger than most of what it gets mixed with, at 55–60 mm standard length against 40–50 mm for the small blackwater species, and it is noticeably deep-bodied and short rather than torpedo-shaped. Adult males add a long, extended dorsal fin. It is an Orinoco fish rather than an Amazon one, restricted to a corner of Venezuela and Colombia, and FishBase carries it as Near Threatened, assessed on 07 August 2019. The 2024 Corydoradinae revision moved it into the resurrected genus Hoplisoma, which is why FishBase, the Catalog of Fishes and Corydoras World now write Hoplisoma concolor while every shop label still says Corydoras concolor.
Care
At 6 cm and deep-bodied it needs more floor than most of the small corys: Seriously Fish asks for 'minimum base dimensions of 80 * 30 cm or equivalent ... for long-term care' and AquaInfo independently gives 80 cm, so we gate at 80 cm of floor and 80 L rather than the 60 cm most of our corydoras get. Keep six or more over soft, rounded sand — AquaInfo is explicit that sharp sand or gravel damages the barbels, that the damage becomes inflammation, and that fish sometimes lose the barbels completely, though they do grow back once the fish is put back on sand. Water is undemanding but not indifferent: Seriously Fish gives 20–26 °C, pH 5.5–7.0 and 18–143 ppm, AquaInfo the tighter 23–26 °C, pH 6.5–7.0 and GH 3–6. Keep a lid on, and net it into a container rather than lifting it out — the pectoral spines are stiff enough to pierce skin.
Diet
Omnivorous bottom forager. Sinking wafers, granules and pellets plus frozen or live bloodworm, Tubifex and daphnia. Make sure food actually reaches the sand — this species will not live on what the fish above it drop.
Tankmate compatibility
Gets along with (213)
Possible with care (143)
Avoid (62)
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
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.
The full disease guide →Sold in Lithuania
These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.
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Frequently asked questions
- What tank size does a Slate Cory need?
- A Slate Cory needs an aquarium of at least 80 litres (21.1 US gallons) with a footprint at least 80 cm (31.5 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Slate Cory need?
- Slate Cory does best at 20–26 °C (68–78.8 °F), pH 5.5–7.5 and a general hardness of 1–10 °dGH.
- What group size does a Slate Cory need?
- Slate Cory is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
- Is the Slate Cory suitable for beginners?
- Slate Cory sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.