Pygmy cory catfish: the nano cory for small planted tanks

The pygmy cory catfish is the smallest of the three common corys, at about 30 mm standard length, and the only one that spends much of its day in mid water rather than on the sand. That makes it the cory to pick for a small planted tank where peppered and panda corys would feel cramped.

Give a group of at least six a tank with a 45 x 30 cm footprint, soft water, and tiny tank mates, and it will shoal in the open where you can actually see it.

Pygmy, panda and peppered corys by size and footprint

All figures come from the Seriously Fish species profiles. Treat them as a working range for keepers rather than hard limits.

Pygmy and panda corys share the same minimum footprint, but a 30 mm fish fills it very differently. You can keep a larger group of pygmies in 41 litres than you could of pandas, and Seriously Fish says as much.

The row that catches people out is hardness. Pygmy corys prefer water under 8 dGH, so hard tap water that suits peppered corys can hold them back.

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Video: Flip Aquatics

Picking a nano tank that actually fits them

Footprint matters more than the litre figure on the box. A tall cube with a 30 cm base gives a mid water shoal less swimming room than a long, low 45 cm tank.

If you are still choosing hardware, our guide to the best nano tanks for aquascaping lists footprints, so you can filter out anything shorter than 45 cm.

Planted setups suit pygmies well. Fine sand, stem plants, and moss give them cover, and a gentle sponge filter keeps the flow low for such a small swimmer.

Tank mates small enough to share with

Seriously Fish describes the pygmy cory as very peaceful but easily intimidated, and too small to compete with larger fish for food. Angelfish, gouramis and bigger catfish may treat it as a snack.

• Similarly sized tetras and rasboras, which pygmies will often school alongside.
• Dwarf cichlids such as Apistogramma, where pygmies act as a calm dither fish in the middle layers.
• Dwarf shrimp, which ignore the corys and clean up what they miss.

Shrimp pairing is the classic nano combination. The same tanks we rate among the best nano tanks for shrimp work for a pygmy cory group, provided the footprint reaches 45 cm.

Feeding and first weeks

Their mouths are tiny. Crush flake or use a fine grade of food, and add small live or frozen foods such as daphnia or baby brine shrimp for colour and condition.

Shop fish this small are easy to lose to a disease you did not see coming. Run new arrivals through a quarantine tank for fish and plants for two weeks before they join an established shrimp or nano community.

Buy six at a minimum and ten or more if the tank allows. A bigger group shoals tighter and spends less time hiding.