Aquarium fish: Dichotomyctere nigroviridis (Tetraodon nigroviridis)
Size: 15 cm
Water temperature: 24-28 ° C
Aquarium volume: 112 l
Dichotomyctere nigroviridis (Tetraodon nigroviridis ) – an aquarium fish from the puffer family with an interesting appearance and behavior. In Poland, unfortunately, incorrect nomenclature has been adopted, which is why T. nigroviridis (Green Spotted Puffer) is called k. Green and is often confused with another very similar species of T. fluviatilis (Green Puffer).
Southeast Asia . A widespread species. Found in India, Sri Lanka, Myanmar, Thailand, Vietnam, Malaysia, Indonesia and the Philippines. It lives in waters of varying degrees of salinity in coastal zones of seas and oceans, and in fresh waters of rivers, streams, lakes and lagoons.
Characteristics and disposition
In nature, it can be up to 15 cm in length, and in aquarium conditions they rarely exceed 10 cm .
Oval body, stocky build, with a broad forehead. The slightly protruding eyes move independently of each other. Body color may vary depending on the occurrence. Adults are usually green, speckled with dark spots and with a white underbelly. In the young, the green tinge is hardly visible.
The fins are poorly developed, partially transparent and slightly tinged with yellow. They do not have pelvic fins or gill covers. The small mouth is equipped with two pairs of strong tooth plates that allow them to crush and split the hard shells of snails or mussels. Gender is indistinguishable. Interestingly, even during DNA testing attempts, They have the characteristic ability to “get puffed up”.
In an emergency, a specially adapted, very stretchy diverticulum of the intestine fills the body with air or water. In addition, they can pretend to be dead by swimming upside down, and their tissue produces a very powerful substance – Tetrodoxin, which is 1000 times more deadly than cyanide. It is often confused with the species T. fluviatilis and T. schoutedeni .
The former is slightly larger, slimmer and has a different pattern on the spine – several large, symmetrical spots separated by stripes . T. schoutedeni is a very rare specimen, which has been invisible in aquaristics for several decades, and has spikes on its lower abdomen. They are not very good swimmers, but they do show great mobility. They like a variety of surroundings and will be happy to search every corner of the aquarium.
In the wild, they can be found singly or in small groups. They have a penchant for gnawing the fins of other free-swimming fish. Adult males are not friendly towards each other, but in a sufficiently large tank, they usually only end up chasing the rival. In the aquarium it is recommended to keep individually or in groups of min. 4 individuals.
Nutrition and feeding
Omnivorous and predatory fish. In natural habitats, a large part of their diet consists of foods of animal origin, such as invertebrates, crustaceans, molluscs. In the aquarium, they can be given dry, frozen and live foods, e.g. krill, shrimp, crab legs, snails, bloodworm, artemia, and adults can also give them scallops, clams, oysters, crayfish and crabs. From time to time, it is worth supplementing the menu with plant foods, e.g.
lettuce, spinach, zucchini. Pufferfish teeth are constantly growing and need to be naturally abraded. Regular feeding of snails in their shells is a must. In case of neglect, they will stop taking food.
For a single individual, it is recommended to min.
112 l aquarium, with a sandy base, partially planted with hardy plants (the more delicate ones can be eaten). Dry twisted, twigs or roots will provide them with extra shelter. They do not like bright lighting that can be suppressed by floating vegetation. Despite the fact that they are also found in fresh water, according to numerous opinions, they will feel better and live longer in slightly salty water – brachic (approx. 1.005 SG).
They are very sensitive to pollution and require excellent water quality . An efficient filter and regular weekly water changes (30-50%) are required. In bad conditions, they quickly lose color and become apathetic – they are not very active, lie on the bottom or swim curled into a ball. They can be kept in a social aquarium, but mates should be chosen carefully. They are considered to be fin-gnawing fish and therefore not suitable for species with long fins and free swimming.
It is best to keep them with tough active fish, such as green argus, Indian shooter, Arius, silver spade.
Reproduction at home is impossible. In 2009, a research group at Florida State University successfully multiplied this species. Sea water is required to produce eggs and fertilize them. These fish are very fertile – an adult female weighing 10 grams has laid about 7,000 eggs.
The eggs are pale yellow, sticky and about 0.5 mm in diameter. Hatching takes place after approx. 72 hours. The fry do not eat for the first 3 days. Artemia was started on the 4th day.
Under natural conditions, the fish spawn directly on the ground or on a flat stone. The male protects the eggs and hatching. After hatching, the parents transfer the larvae to a previously dug hole in the substrate.
Dichotomyctere nigroviridis (T. Nigroviridis) – is one of the model species in genetics.
Its genome was sequenced in 2004 and has the smallest known genome among vertebrates, around 340 million base pairs.