Order Tetraodontiformes.
Representatives of the order are close to Perciformes. They differ from the latter in that their jaw bones are tightly connected to the premaxillary bones, forming a beak. The body of these fish is usually short; many species have intestinal outgrowths forming a sac used to inflate the body. Pelvic fins are either absent or located below the pectoral fins. Predators. They have a vicious disposition. Females are larger and more vicious than males. High-strength teeth.
They owe their remarkable abilities to a special body and jaw structure. Nimbly paddling with their pectoral fins, they approach their prey and grab it with their miniature mouth equipped with crushing plates. The body is covered with spines. In times of danger, they can inflate like a ball to appear “too big to eat” to an enemy, while gnashing their teeth, smacking, and bubbling, which deters opponents.
Suborder Tetraodontidei
In representatives of the suborder, jaw teeth fuse together, forming a powerful “beak” resembling a parrot’s beak. The caudal fin usually functions as a rudder, and movement is carried out mainly with the help of pectoral fins and short, high dorsal and anal fins shifted far back. Pelvic fins are absent. Tetraodontids are mostly shallow-water fish associated with coral reefs, with only a few belonging to brackish-water and freshwater forms.
Fish have special sacs that fill with water or air, causing the body to inflate, turning into a spiny ball, becoming invulnerable to enemies. Keep in a large species aquarium with plenty of hiding places. They are the best snail eaters, completely destroying mollusks. In some species, internal organs or body slime are poisonous. pH 7-8; dH 6-15°; T 22-28°C.
Family Tetraodontidae
The vast majority of species originate from South and Southeast Asia, with only six species living in Africa and even fewer in South America. Only 32 of 185 species can be characterized as truly freshwater fish. The rest are mostly marine fish (some species, however, temporarily inhabit brackish and even fresh water). Representatives of the family got their name from their peculiar tooth structure: they are fused, and there are two teeth on each jaw.
Body without scales, elongated-ovoid shape, rounded, may have small prickles. The skin on the body is naked or covered with small bony plates. Eyes are large, mobile. Gill slits are very small, having the appearance of small holes lying directly in front of the pectoral fins. Puffers can inflate by filling their body with water or air; if spines are present, they erect.
Fish of the genera Tetraodon, Carinotetraodon, Monotrete, Auriglobus, Fugu (only Fugu orbimaculatus) live in fresh water. Of these, sometimes imported are Carinotetraodon imitator, lorteti, irrubesco, salivator, C. travancoricus, Colomesus asellus, Tetraodon lineatus, T. duboisi, T. mbu, T. miurus, T. palembangensis, T. pustulatus, T. schoutedeni and Monotrete abei, baileyi, suvattii.
Most representatives of the family, mainly puffers, regardless of size, have an unaccommodating character, so they should not be kept with other fish. Aggressiveness decreases in a spacious aquarium with plenty of hiding places. Plants used for decoration should have a fast growth rate, because they nibble on plants, primarily those with soft leaves. They like shady places and shelters. Most species prefer caves and shelters made of large stones and wood.
Aeration, filtration, and water changes (up to a third of the volume weekly) are mandatory. Freshwater fish have a very strong need for oxygen; its deficiency leads to suffocation and, as a rule, severe stress. The presence of a diffuser in the aquarium is the only correct solution to the problem. Carnivorous species in the aquarium eat all kinds of live foods, mollusks, worms, small fish, etc.
They mature at 1-3 years. Females are generally paler, larger, and wider than males. During the spawning period, her abdomen rounds out (a transverse fold forms in the anal region) and a pear-shaped ovipositor appears. Fish guard their offspring. Lifespan in an aquarium is 5-15 years. Hardness 5-20°, pH 6.5-7.5, temperature 22-30°C, salinity 2-5, up to 15%.
Genus Auriglobus.
— Golden Puffer, Avocado Puffer, Bronze Puffer — Auriglobus modestus [Bleeker, 1851]. Synonym: Chonerhinos africanus, modestus, Tetraodon modestus. Thailand, Vietnam, Malaysia, Indonesia. 10 cm. Has an unusual graceful body shape. Its body is not decorated with a pattern at all, but has golden, green, and bronze shades. The belly is pale creamy white, and the upper part is iridescent green-yellow. The most noticeable feature is the yellow eyes. Fins are transparent.
These are very active and fast fish compared to most other puffer species, making it difficult to find tank mates other than fast top-dwelling danios. Extremely aggressive, fish and most invertebrates will be attacked and eaten. Sandy substrate, driftwood, and caves for hiding, floating vegetation to reduce lighting. Long-stemmed plants are needed when keeping with other fish where they can hide. Freshwater, they can be kept in clean fresh water, do not require water salinization.
Extremely sensitive to nitrites and ammonia in the water. Require efficient filtration and weekly water changes. Their diet includes live and frozen aquarium foods (but not fish), snails, krill, frozen shrimp, mollusks, and crustaceans. These fish must receive snails and other hard foods daily to prevent teeth from overgrowing, otherwise teeth will need to be trimmed 3-4 times a year. Live up to 10 years. T 23-26°C; dH 4-18°; pH 6.0-7.8.
Genus Chelonodon.
— Milk Spotted Pufferfish, Toadfish — Chelonodon patoca [Hamilton, 1822]. Synonym: Tetrodon dissutidens, patoca, Chelonodon, Arothron kappa. Indo-Pacific region, East Africa, South and East Asia, Malay Archipelago – coastal brackish waters. 30 cm, in an aquarium up to 19 cm. Coloration is beige-olive with 2 dark wedge-shaped stripes near the pectoral and dorsal fins. Oval white spots are scattered all over the body. A yellow stripe from the lower part of the head to the tail. Belly is white. Slightly rounded caudal fin is dark yellow.
This species is relatively sociable with other aquarium inhabitants, and even with conspecifics. It is the most dangerous due to its toxicity. This toxin is known as “fugu”; its consumption leads to sudden death. As a result, in the aquarium, it can cause the death of fish in the immediate vicinity of a sick or frightened pufferfish. Mature after 2 years. pH about 8; dH 18-30°; Temperature 23-28°C, salinity up to 8%.
Identification: Genus Auriglobus, Chelonodon.
Carinotetraodon borneensis, irrubesco, lorteti.
Polypterus palmas, senegalus, weeksii. 
