Tetraodon nigroviridis

Green Spotted Puffer

Classification

Tetraodontidae

Distribution

A widespread species, being found in India, Sri Lanka, Myanmar, Thailand, Cambodia, Vietnam, Malaysia, Indonesia and the Philippines.

Habitat

Occurs in brackish water in coastal areas; freshwater rivers, streams, lakes and flooded areas.

Maximum Standard Length

6.8″ (17cm), although this is considered very large in aquaria.

Aquarium SizeTop ↑

48″ x 12″ x 12″ (120cm x 30cm x 30cm) – 110 litres.

Maintenance

Best kept in a heavily-planted setup with twisted roots and branches to provide additional cover, although soft-leaved plants may be chewed by the fish. Leave some open spaces inbetween for swimming, as this is an active species. The use of a sandy substrate and floating plants to diffuse the light is also recommended. This species is very sensitive to deteriorating water conditions, so regular partial water changes are a must. Although it’s often considered a true freshwater species, it tends to be more long-lived with the addition of marine salt to a sg of around 1.005 in aquaria. It can also be maintained in freshwater, however.

Water Conditions

Temperature: 75-82°F (24-28°C)

pH: 7.5-8.5

Hardness: 10-20°H

Diet

Relishes all kinds of shellfish, as well as worms and other live and frozen foods. It should be fed snails and unshelled shellfish (such as crab legs, prawns etc.) regularly in order to maintain its sharp teeth. As with other puffers, these grow continuously and become a problem for the fish if they’re not kept ground down.

Behaviour and CompatibilityTop ↑

Can be kept in a community tank, but caution should be exercised when choosing tankmates, as it tends to nip the fins of slow-moving or long-finned fish. Some individuals also become particularly spiteful with age. It’s best kept with robust, active species such as scats, archerfish, Arius catfish and perhaps monos.

It’s not a good idea to keep more than one of these per tank unless a lot of space is available, as they’re usually pretty belligerent toward conspecifics. Males in particular will fight constantly. If you want to keep a group try to buy at least 4 fish, so that any aggression is dissipated to an extent and arrange the decor so that there are many hiding places.

Sexual Dimorphism

No information available. Seemingly impossible to sex by external characteristics.

Reproduction

Not easy but has been spawned in aquaria. The fish will spawn only in brackish water, and should also be provided with some flat rock surfaces to act as potential spawning sites. The eggs are laid directly onto the substrate or a flat rock, and are guarded by the male. They hatch in around 7 days, and in a similar fashion to many cichlids, the fry are moved to a pre-excavated pit in the substrate where they continue to be guarded by the male. The fry are purportedly very challenging to raise, most foods apparently being unsuitable for them. Some success has been had via the use of Cyclops nauplii.

NotesTop ↑

Puffer fish are so called as they have the ability to inflate their elastic stomachs with water or air. This is usually a response to some kind of threat, although in the aquarium many specimens appear to inflate themselves for no apparent reason. The fish becomes 2 or 3 times it’s normal size, which makes the fish both big enough to scare away many potential predators, and difficult to swallow.

Many parts of the body of puffers contain the deadly neurotoxin tetrodoxin. This is the same poison found in the notorious blue-ringed octopus. When ingested in sufficient quantities, it can cause paralysis and death. As yet there is no known antitoxin and to humans it is over 1000 times deadlier than cyanide. Grotesquely, the victim usually remains conscious as he or she becomes paralysed. It’s a famous delicacy in Japan, but is prepared only by highly-trained chefs, and even then many people have died from eating it.

T. nigroviridis is often confused with its similar looking relatives T. fluviatilis, and T. schoutedeni. It can be distinguished from these by its more rounded shape when compared to fluviatilis and lack of spines on its belly (present in schoutedeni. Try to be sure which species you’re buying, as only fluviatilis is a true brackish species. The green spotted puffer is an ideal beginners’ puffer but is certainly not a fish for the general community, although unfortunately it’s often sold as such. When kept correctly it’s an inquisitive and interesting species that can exhibit real personality traits.