Rainbow Snakehead

With its long, cylindrical body, flat head and fin running the whole length of its back, the rainbow snakehead is a typical snakehead; but it stays at 20 cm and is one of the most colorful species. Its bluish gray-brown body is decorated with orange spots, and its fins with orange-red and blue-white edges.

It breathes air from the surface with a special organ above its gills; it can drown if it cannot reach the surface. The male carries the eggs in his mouth.

Legal status: Snakeheads are considered invasive species in some countries; in the USA, for example, unpermitted import and transport of all snakehead species is banned. Check local regulations before buying and never release any snakehead into the wild.

It lives in shallow, vegetated ponds and swamps of the Brahmaputra basin in the Assam region of India. The region is subtropical; the water cools noticeably in winter.

• Volume: at least 120 liters for a single fish, 150–200 liters for a pair.
• Lid: a very tight lid; it both jumps and escapes through the smallest gap. Leave an air gap between the water surface and the lid.
• Decor: dense plants, roots, floating plants and hiding places; dim light.
• Season: lowering the temperature to 16–18°C for a few months in winter supports its health and willingness to breed.

Carnivorous. Worms, shrimp, mussels, fish fillet, frozen bloodworms and sinking pellets. Live feeder fish become a habit and carry disease. It is prone to obesity; feed adults every two to three days.

An ambush predator; it eats fish and shrimp that fit in its mouth. It is territorial toward its own kind; apart from a compatible pair, more than one individual will fight.

Good companions: a species tank is best. In a large aquarium it can be tried with calm species too big for its mouth that can stand up for themselves.

Avoid: small fish, shrimp, fin-nipping species, other snakeheads.

Alone or a compatible pair. The safest way to get a pair is to raise several juveniles together and pick the two that pair off.

The male takes the eggs laid by the female into his mouth and incubates them; after the fry leave the mouth they remain under the parents' protection for a while. Breeding begins when the water warms up after a cool winter period.

• Escape and drying out: the most common cause of loss.
• Obesity: in overfed fish.
• Constantly high temperature: a shortened lifespan is reported in fish not given a cool period.

Hard to tell apart. Males are usually more colorful, with larger heads and longer fins; females are plumper and plainer.