Green spotted puffer fish (Tetraodon nigroviridis) require brackish water, live foods and do not always co-habitate well with other species, so they are challenging for novices. Nevertheless, if you provide them with a large, sparsely populated tank with properly calibrated water chemistry, they are likely to live for many years. Realize that the cute little inch-long fish swimming in a pet store aquarium will grow into an aggressive, 6-inch-long eating machine, so a large tank is necessary.
Tank Size and Decor
Green spotted puffer fish eventually require at least 30 gallons of space, but always provide the largest tank possible. If you keep a puffer with other fish, scale the tank size up accordingly. Green spotted puffer fish may live peacefully with large, active species, such as scats and archerfish; they may harass very small or timid fish. Additionally, green spotted puffers do not tolerate others of their own kind, so you must house them singly. Always be sure to incorporate plenty of plants -- whether live or artificial -- and other items to provide cover for your puffer. Green spotted puffers may eat live plants, so opt for artificial plants if you do not want to replace the live plants periodically.
Wild green spotted puffer fish live in coastal areas, where fresh and saltwater meet. While green spotted puffers may survive in freshwater while they are young, they require brackish water as adults. Use a hygrometer to measure the specific gravity of the tank water. Ideally, green spotted puffers prefer specific gravities of 1.005. However, it is important to make any changes gradually. Many pet stores keep their young puffer fish in freshwater aquariums; if you purchase a freshwater-reared fish, place him in a similar tank for the first few days. After your new pet has acclimated to his new home, slowly begin increasing the salinity of the tank by adding marine salt.
Additional Water Parameters
Green spotted puffers prefer water temperatures between 75 and 82 degrees Fahrenheit. Use an aquarium test kit to monitor the tank’s water chemistry. They require slightly alkaline water, with a pH of 7.5 to 8.5. Because they are messy eaters, green spotted puffer fish create a great deal of debris in the tank, so be sure to use a high-quality filter to keep the water clean. Additionally, conduct a partial water change every week.
Green Puffer Diet
Feed your puffer fish frozen or live bloodworms, shrimp and other invertebrates to mimic their wild diet. As with other puffer fish, green spotted puffers have teeth that grow continuously. To prevent overgrowth and associated health problems, be sure to feed hard prey items to your fish on a regular basis. Snails, prawns and crab legs are all excellent supplements to their staple diet. When you first purchase your puffer fish, he will require very small food, but you should scale up the size of his food as he grows. For example, as a rule of thumb, your puffer can eat snails that are about the same size as his eyeball.