Green spotted puffer

Dichotomyctere nigroviridis

FreshwaterBrackishSaltwaterFish

Care at a glance

Temperature: 75–82°F (24–28°C)
pH: 7.5–8.5
Adult size: 5.9 in (15 cm)
Minimum tank: 32 gal (120 L)
Temperament: Aggressive
Social behavior: Solitary
Swim level: Middle
Difficulty: Difficult
Breeding: No record
Rarity: Very rare
Reef safe: Not reef safe
Origin: South Asia, South East Asia
Family: Tetraodontidae

Overview

The green spotted puffer is an aggressive, territorial fish that is best kept alone, despite its harmless looks. It will nip and attack tankmates, so treat it as a solitary species-tank fish rather than a community member. Young fish live in fresh to lightly brackish water, but they must be moved to strongly brackish and eventually near-marine water as they mature, or they slowly decline. Its teeth grow throughout life, so feed hard-shelled foods such as snails, clams, mussels, and shell-on shrimp. Give it clean, salty water and swimming space. A single adult needs a tank of around 120 liters or larger.

In the wild

The green spotted puffer is found across South and Southeast Asia in coastal rivers, estuaries, and mangroves, where the water shifts from fresh to fully marine with the tides. It is euryhaline, and its needs change with age. Juveniles start in fresh or slightly brackish water, but adults are healthiest in high-end brackish to marine conditions. Raise the salt gradually as the fish grows, keep the pH high between 7.5 and 8.5, and hold the temperature from 24 to 28 C. Use hard, alkaline water, a mature filter, and open swimming space with some rock or wood.

Good to know

The green spotted puffer belongs to the family Tetraodontidae and was long known as Tetraodon nigroviridis. Adults reach about 15 cm, with a bright green back covered in dark spots and a clean white belly. Like all true puffers it has four fused, beak-like teeth and can swallow water to inflate into a ball. Its skin and organs carry tetrodotoxin, a powerful natural poison. Aquarium breeding is essentially undocumented, and the fish in shops are wild caught from brackish coastal waters.

Did you know

The green spotted puffer has one of the most compact genomes of any backboned animal, packing a similar set of genes into far less DNA than most vertebrates. Because of that, scientists sequenced it as a reference to help make sense of the much larger human genome.