Vermiculated Sailfin Pleco

The vermiculated sailfin pleco is a large suckermouth catfish sold in shops alongside the common pleco (P. pardalis) as an "algae eater" or "sailfin pleco." The two species are very similar; the easiest way to tell them apart is the belly pattern: in P. disjunctivus the dark spots on the belly join to form winding, worm-track lines, while in P. pardalis they are separate spots. Hybrids of the two species are also seen in the trade.

Juveniles are sold at 5 cm, but it reaches 40–50 cm, even larger in the wild, and lives for more than 15 years. This species has become invasive after being released into the wild in the USA (Florida), Mexico, Taiwan and Southeast Asia, harming local fisheries and coastal ecosystems. Individuals that outgrow their aquarium must never be released into the wild; they should be handed over to an aquarist or a store.

It lives in slow-flowing river channels, lakes and floodplains of the Madeira basin. It digs tunnels in muddy banks and can tolerate even low-oxygen water. Like other Pterygoplichthys species, it can gulp air from the surface when needed.

• Volume: At least 750 liters and 200 cm in length for one adult; a pond is more suitable.
• Filter: A very powerful canister filter or sump, with a 40% water change every week.
• Decor: Large roots, sturdy caves. It uproots and eats plants.
• Water: 24–27°C; it adapts to a wide range of parameters.

An omnivore with a mainly herbivorous diet. Algae and vegetable wafers, blanched zucchini, cucumber, potato, spinach and peas should be the staple; frozen food can be given occasionally. Rasping on wood aids its digestion.

It is peaceful toward other species, but as it grows it becomes territorial toward its own kind and other large bottom dwellers. It is known to suck the slime coat of slow, flat-bodied fish.

Good companions: Large, fast fish: oscars, silver dollars, large barbs, large cichlids (in a very large aquarium).

Avoid: Small aquariums, goldfish, slow, flat-bodied fish such as discus and angelfish, planted layouts.

In a home aquarium a single individual is kept. A group is only possible in ponds or very large systems. Since it is a tropical species, individuals kept in an outdoor pond must be moved to a heated environment during the winter months.

In the wild it breeds in tunnels it digs in the banks; the male guards the eggs. It does not breed in the aquarium; commercial breeding is done in ponds.

Very hardy. Problems almost always stem from insufficient space and water quality. The heavy waste load raises nitrate quickly.

Difficult to tell apart externally. In mature males the pectoral fin spines may be thicker and covered with odontodes; the difference in the genital papilla can be seen on close inspection.