Gouramis

The honey gourami is the gentle one: 2 inches (5 cm), 14 gallons (54 liters), marked easy and peaceful, and safe with small tetras. It eats shrimplets and may pick off small shrimp, so it does not suit a shrimp breeding tank. The pearl gourami is the best of the larger species, 4.7 inches (12 cm) in 29 gallons (111 liters), easy and peaceful even as a male. The thick-lipped gourami is a hardy 3.5 inch (9 cm) fish for 20 gallons. The dwarf gourami is the one in every shop, 3 inches (7.5 cm) in 10 gallons (38 liters). It is marked medium because the trade stock carries a virus that kills fish within months of purchase. Buy from a source you trust and quarantine. The pygmy gourami stays at 1.6 inches (4 cm), croaks and lists 10 gallons (38 liters).

Most male gouramis build bubble nests and defend the water around them. Two male dwarf or three spot gouramis in a 20 gallon fight until one is cornered permanently; keep one male with one or two females, or one gourami per tank. The paradise fish is listed as one male per tank, and the combtail gourami, the climbing perch and the pikeheads are marked aggressive and solitary. Many gouramis live in groups when the tank has cover, including the pearl, honey and croaking gouramis. The chocolate gouramis live in groups too, with six or more for the Vaillant's and crossband chocolate gouramis and the eyespot gourami. The thick-lipped, three spot, moonlight, banded and snakeskin gouramis can be kept as a pair or a small group. All of them need to reach the surface: floating plants, no strong surface current, and a lid that keeps the air above the water warm.

The licorice gouramis stay between 0.9 and 1.6 inches (2.4 and 4 cm) and list 5 to 11 gallons (20 to 40 liters). They are marked difficult across the board. They want very soft water with a pH in the 4s and 5s, leaf litter, dim light, live or frozen food and no boisterous company. Many are threatened in the wild and are kept by specialist breeders in species tanks. The chocolate gourami is a little easier, marked medium at 2 inches (5 cm) in 17 gallons (65 liters), but it wants heat, 79–88°F (26–31°C), and the same soft acidic water; the crossband, sharpnose and Vaillant's chocolate gouramis are marked difficult.

The paradise fish lists 50–72°F (10–22°C) and suits an unheated tank or a summer pond, at 3.1 inches (8 cm) in 25 gallons (95 liters). The Hong Kong and round-tail paradise fish take similar cool water. At the other end of the list the giant gourami reaches 27.6 inches (70 cm), lists 180 gallons (680 liters) and lives for decades. The giant red tail and seven-banded giant gouramis reach 19.7 inches (50 cm) and list 172 gallons (650 liters) and 264 gallons (1,000 liters). The kissing gourami and the snakeskin gourami both reach 9.8 inches (25 cm) and are sold as small community fish, which they are not.