What tank size does a Tail-Spot Pygmy Cory need?

A Tail-Spot Pygmy Cory needs an aquarium of at least 54 litres (14.3 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 Tail-Spot Pygmy Cory need?

Tail-Spot Pygmy Cory does best at 20–28 °C (68–82.4 °F), pH 6–8 and a general hardness of 2–15 °dGH.

What group size does a Tail-Spot Pygmy Cory need?

Tail-Spot Pygmy Cory is a social species — keep a group of at least 10 so natural behaviour emerges and stress stays low.

Is the Tail-Spot Pygmy Cory suitable for beginners?

Tail-Spot Pygmy 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.

Species library

Tail-Spot Pygmy Cory

Gastrodermus hastatus

Callichthyidae

FishDifficulty: ●●●○○Data: well-established

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About

The tail-spot pygmy cory is the dwarf that forgot to be a bottom fish. Seriously Fish records that it 'tends to swim in midwater and spends a large proportion of its time away from the substrate', with a body built for it: a relatively large eye, a more terminal mouth position, a more strongly forked caudal fin and a more symmetrical shape than most of its congeners. The diagnostic mark is a dark, roughly diamond-shaped spot on the caudal peduncle, which AquaInfo describes as black with a clear white or pale-yellow rim. That spot is how you separate the three dwarf cories on sight: the pygmy cory (Gastrodermus pygmaeus, still sold everywhere as Corydoras pygmaeus) has no tail spot but carries a dark lateral stripe, and the salt and pepper cory (habrosus) is blotched and works the sand. In the wild it forms mixed shoals with similarly patterned small characins — Seriously Fish names Serrapinnus kriegi, Aphyocharax nattereri and Hyphessobrycon elachys — and in the aquarium the consequences are practical: it wants an open midwater lane to shoal in and real zooplankton in the diet, not only sinking wafers. Its name is changing too. The 2024 Corydoradinae revision moved it into the resurrected genus Gastrodermus, the 'Elegans' group of lineage 5, and FishBase, Corydoras World and the Catalog of Fishes now all write Gastrodermus hastatus while shops and older books still say Corydoras hastatus. Gastrodermus is masculine, so the adjective keeps its -us — the same revision turns Corydoras habrosus into the neuter Hoplisoma habrosum, which is exactly why the new genus can never be guessed from a relative.

Care

Keep 10 or more — Seriously Fish asks for at least 4-6 and 'ideally 10 or more' — over soft, clean sand with gentle flow and a clear midwater lane to shoal in. Despite the 3 cm size Seriously Fish calls it unsuitable for modern nano aquaria and recommends base dimensions of at least 60 × 30 cm. Feed live or frozen Daphnia and Artemia alongside sinking micro-foods, and house it only with tiny, slow-feeding tankmates.

Diet

Foraging omnivore partly adapted to pelagic zooplankton; make live or frozen Daphnia, Artemia and cyclops a staple, with sinking micro-pellets and crushed wafers for the substrate half of its feeding.

Tankmate compatibility

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.

All the methods, with diagrams

Also in these lists

Fish for a 54 litre tank Shrimp-safe fish Peaceful community fish Fish for a 112 litre tank

Similar species

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

Sixray Corydoras Salt and Pepper Cory Venezuelan Cory Agassiz's Cory Green Laser Cory Horseman's Cory

Health

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

White spot (ich)

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.

aquasharks.lt

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

Frequently asked questions

What tank size does a Tail-Spot Pygmy Cory need?: A Tail-Spot Pygmy Cory needs an aquarium of at least 54 litres (14.3 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 Tail-Spot Pygmy Cory need?: Tail-Spot Pygmy Cory does best at 20–28 °C (68–82.4 °F), pH 6–8 and a general hardness of 2–15 °dGH.
What group size does a Tail-Spot Pygmy Cory need?: Tail-Spot Pygmy Cory is a social species — keep a group of at least 10 so natural behaviour emerges and stress stays low.
Is the Tail-Spot Pygmy Cory suitable for beginners?: Tail-Spot Pygmy 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.

Sources

Water & tank

Temperature20–28°C

Optimal temp.24–26°C

pH6–8

Hardness (GH)2–15°d

Carbonate (KH)0–8°d

OriginAmazon Basin, La Plata–Paraná basin (natural range)

Adult size3.2 cm

Min. volume≥ 54 L

Min. tank length≥ 60 cm

Group size≥ 10

Swimming zoneMid

TemperamentPeaceful

Water typeFreshwater

FlowLow

Lifespan~5 yrs

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