Everyone knows that Common plecs and Oscars get big, but there are several other, commonly sold species that also belong to the foot-long club.

Silver Shark, Balantiocheilus melanopterus

A mainstay of the tropical fishkeeping hobby, Silver sharks are peaceful and easy to keep. The downside is their maximum size of 14”/35cm which they can and do achieve, even in average sized aquariums. To house them properly Silver sharks ideally need a six foot (180cm) tank, and larger still for an adult group. 

Clown Loach, Chromobotia macracantha

One of the most popular tropical fish, Clown loach have striking markings, funny antics and eat nuisance snails too. But like the Silver shark these are 14” fish when adult and need to be kept in large shoals to be happy. A six to eight foot tank (72-96"/180-240cm) is needed long term, as they are prone to stunting when kept in small tanks

Banded Leporinus, Leporinus fasciatus and L.affinis

Silver shark-like in shape, Banded Leporinus comprise two species and most are imported from the wild. They are prone to harassing other aquarium fish when kept in cramped conditions and need a lot of glide space to exercise. See an adult Leporinus swimming and you’ll see why they need, long, roomy accommodation.

Chinese Algae Eater, Gyrinocheilus aymonieri

Not a lot of people know this, but those small, Golden algae eaters and Chinese algae eaters can grow to a foot long (12"/30cm) in the wild. Excellent algae eaters when small they become more territorial and less tolerant of their own kind and other fish as they grow, preferring instead to stake out a large area of the tank for themselves. Hardy, temperature tolerant, but requiring large tanks long term. 

Kissing Gourami, Helostoma temminkii

So-called because of the kissing behaviour, Pink kissing gourami are actually green in their wild, uncultivated form and grow to a foot long (12"/30cm). Popular food fish in their native Cambodia, Kissing gourami are peaceful in the aquarium but are long-lived and become very large fish. Snakeskin gourami reach a close second at 10”/25cm total length. Far bigger than you see in the shops.