Spotted hoplo (Megalechis thoracata) care guide

Group

Freshwater fish

Other names

Hoplo, Spotted hoplo catfish, Armoured catfish, Hoplosternum thoracatum, Megalechis personata, Callichthys exaratus

Family

Callichthyidae (armoured catfishes)

Origin

Widespread in South America: Amazon, Orinoco, Paraná–Paraguay basins, coastal rivers of the Guianas and northern Brazil, and Trinidad.

Water

freshwater

Maximum size

15.5 cm

Temperature

17–28°C

pH

5.5–8.2

Hardness

Soft to hard (adaptable)

Minimum tank

160 litres

Care level

beginner

Temperament

peaceful

Care

A hardy, robust armoured catfish that grows to about 15 cm. It is happy alone but more interesting in a small group. As our estimate, a tank of at least 100 × 40 cm (around 160 litres) suits a few adults. In the wild it lives in still, weedy, low-oxygen pools and can survive poor conditions, because it is an obligate air-breather (FishBase) that must reach the surface to gulp air. Always leave access to the surface and a little air space under a well-fitting lid, as hoplos can jump. Give it a soft sand or smooth gravel substrate, wood or caves for cover, and floating plants; PlanetCatfish suggests floating plants such as water wisteria for the males to anchor bubble nests. It is very adaptable: PlanetCatfish gives 17–28 °C and pH 5.5–8.2. Being able to survive poor water does not mean it should have to, so keep up regular water changes and good filtration, as it is a big, messy eater. Identification and sexing: an all-over greyish, spotted fish; it differs from Megalechis picta by having no obvious dark vertical band in the tail fin. Mature males have a thickened first pectoral-fin ray that turns orange-brown to scarlet in breeding condition. The name comes from Greek megas, large, and lekis, plate, after the enlarged bony plates of mature males. Older names include Hoplosternum thoracatum and Megalechis personata; it is still sometimes sold as "Hoplosternum". It is a common aquarium fish. FishBase lists it as Least Concern on the IUCN Red List (assessed 2020). Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=14); FishBase (fishbase.se/summary/Megalechis-thoracata.html). Checked October 2026.

Diet

Not a fussy eater: it accepts most foods, and PlanetCatfish recommends bloodworm and sinking catfish tablets as the best staples. Add sinking pellets, prawn and other frozen foods for variety. Larger fish can be greedy and boisterous at feeding time, so make sure slower tankmates get fed.

Breeding

A bubble-nest builder. The male builds a nest of bubbles and plant pieces under floating plants (or a floating lid or tile) and guards it. Condition a pair or a male with a few females on plenty of live and frozen food; a cooler water change can trigger spawning. Eggs are laid into the nest and, according to PlanetCatfish, hatch in about 4 days, with the fry free-swimming about 2 days later. Remove the eggs or the female once spawning ends, as the male may become aggressive. Feed the fry newly hatched brine shrimp.

Compatibility and tank mates

Peaceful and not predatory, so it suits most community tanks with fish too large to be swallowed accidentally. PlanetCatfish notes that larger specimens can be downright boisterous at feeding time. Good companions include medium-sized tetras, barbs, gouramis, peaceful cichlids and other robust catfish. Males guarding a bubble nest can become territorial.

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