|Distribution||Lower Tocantins River basin, Brazil.|
|Sexual Dimorphism||Males possibly more heavily spined over the whole body. The most reliable way of sexing in such a large species is to examine the genital papilla, which is blunter in male specimens.|
|Maximum Size||Up to 1m (39.4") SL, although 60cm (23.6") is more common. The huge lyre-shaped tail must also be taken into account.|
|Temperature||23-29 deg C (73-84 deg F). Highly oxygenated water essential.|
|Water Parameters||pH: 6.0-7.2, dH: up to 12 degrees.|
|Compatibility||Community of large, robust fish only|
|Lighting||Dim (can be brighter if diffused by the decor)|
The mighty Adonis Plec was originally described from the lower Rio Tocantins, but is thought to have a much wider distribution throughout the Amazon basin. This is a giant amongst suckermouth catfish, which is only really suited to the most substantial home aquarium installations and public aquaria. Indeed, the tank must be of vast proportions with powerful, oversized filtration to match. The substrate should consist of soft sand with huge pieces of bogwood arranged to create a number of shady caves and crevices. Rockwork can also be provided, but you must ensure this is heavy enough and stable enough not to be disturbed by the movement of this big catfish. There should be brisk water movement and a high level of oxygenation, perhaps provided by powerheads (in addition to the current generated by the filtration). Dim lighting is preferable, but this can be brighter if diffused by the decor. It is best to keep only one Adonis Plec per tank, as these fish can be fiercely territorial with conspecifics and other bottom dwellers that occupy the same niche. It is not unknown for mature specimens to harass and kill other large plecs and similar species when kept in slightly cramped quarters, so choose tankmates cautiously and observe carefully. The most suitable tankmates would be medium-large sized fish which occupy the mid to upper levels of the water column, such as sizeable barbs, big Anostomids (headstanders), Brycon spp., Distichodus spp., Metynnis/Myleus spp., pike cichlids etc. Whilst juveniles may be fairly slender, they will grow at an alarming rate, quickly becoming much more robust. Additionally, the bright white spots on the body soon become relatively smaller and fewer in number, with some large adults being completely spot-free. May also be seen on sale as Polka Dot Lyre Tail Pleco. An albino variant is sometimes available.
Omnivorous. Smaller specimens can be offered bloodworm, vitamin-enriched brineshrimp, Mysis shrimp etc. Larger specimens will enjoy prawns, cockles, mussels, crab, crayfish etc. Will also take large sinking catfish pellets, algae wafers, sinking carnivore pellets, plus many fruits and vegetables.
There is but a single account of this species having been bred in the home aquarium - however details seem to be few and far between. They are reported to be cave spawners, with the male exhibiting parental care.