Acraniata are represented by a sole preparation of the lancelet in the introductory showcase. The latter includes also a scheme demonstrating historical and phylogenetic relationships among the fish and fish-like vertebrates, as well as a small display of lampreys and myxines.
The next go cartilaginous fish (sharks and rays). This class of vertebrate animals combines about 600 species, which have virtually no bones, as their skeleton is made of cartilage. They live mainly in marine waters, with exception of some inhabitants of the Amazon. One can see here the widespread prickly shark that lives also in the Black Sea; the saw-fish having really the saw-like rostrum; electric ray producing electrical discharges; and stingray, which its tail having a thorn with venom glands at the base. There is also a stuffed specimen of the largest of the rays, the giant manta ray. The showcase displays also chimera, a peculiar deep sea cartilaginous fish with really strange appearance.
More than 20,000 species of the contemporary fish belong to the class of bony fish, with their skeleton almost always being composed entirely of bones, and with the gills being covered by the gill cover. This display begins with the lungfish having a sort of “lungs” to breathe atmospheric air. Belonging here is the famous coelacanth, which gypsum mould is located in the center of the hall. It is to be recalled that discovery of the coelacanth was one of the biggest zoological sensations of the 20th century; this species belongs to the lobe-finned fish thought to having extinct many millions of years ago. They are famous for the fact that representatives of the lobe-finned fish had once given rise to a group of amphibians, from which evolution of terrestrial tetrapods had started.
The giant manta ray The sturgeon The alligator gar
Following are ganoid fish with a few species of several ancient groups largely extinct to date. So these are real “living fossils”. The most interesting among them are sturgeons, many of which are now among the very rare “Red Data Book” species. The exhibition displays sturgeon, stellate sturgeon, Atlantic and Siberian sturgeon, huge stuffed beluga, three species of Central Asian sturgeon, and paddlefish from China.
Exotic species of the ganoid fish are mudfish, Nile polypterus, and alligator gar. The latter are peculiar by their very strong flake. All of these fish tolerate lack of oxygen and able to live in swampy waters.
The main part of the fish exhibition consists of the true bony fishes, which include the vast majority (more than 30 orders, about 20,000 species) of the Recent fish. Despite the overall morphological similarity dictated by the need to move relatively quickly in a fairly dense aquatic environment, the bony fish show a great variety of parts of their body, color, behavior, food preferences and lifestyle in general.
Among clupeiform fish taking the first place in the world fisheries, displayed are both species widely distributed in the oceans (ocean herring, bongos, sardinell, iwashi) and fish of internal Russian seas (the Black Sea and the Volga River herring, sprat).
Of commercial importance are many species of the order Salmoniformes famous for their high taste.
Among esociform fish one can see the most dangerous predator of our rivers, the commom pike.
There is a number of marine fish inhabiting moderate depths and making nightly vertical migrations to the surface, which are represented in the exhibition by some Stomiidae. Some of them have glowing organs on their body surface.
Peculiar are so called elephantfish inhabiting African muddy fresh water. These fish have underdeveloped eyes, but there are a large number of sensitive cells and weak electrical organs that allowing them to orient themselves in space.
Among Anguilliform fish of particular interest is the European eel making distant spawning migration from the European rivers to the Sargasso Sea.
Of the Cyprinoid fish which include about half of all species of the freshwater fish found in Eurasia, Africa and North America (more than 6000 species), the best presented are carp freshwater fish fauna of Russia. Among valuable commercial fish are carp, roach, bream, white-eye, sabrefish, skygazer, grass carp and silver carp. The last two Far Eastern species are objects of artificial breeding, they have been introduced in the European part of Russia, where they widely settled.
Among interesting exhibits is electric eel that lives in fresh waters of S America. This fish has a powerful electric organ located at the rear of the body, which can emit the discharge voltage of 350 volts.
The soft-finned fish are important commercial species (cod, saffron cod, polar cod, whiting), and among ophidiiform fish of undoubted interest is the blindfish, which has reduced eyes because of living in the waters of dark caves.
The order of beloniform fish is represented by well-known valuable saury of Far East. Belonging here are also flying fishes.
Many species of the gasterosteiform and syngnathiform fish are characterized by peculiar nurture: stickleback spawn in a secure nest, while the pipefish male bears eggs in a special chamber located on its belly.
The berycoid fish are very diverse, They are inhabitants of the warm aquatories of the World oceans, including both shallow and deep-sea waters.
Several showcases are devoted to the most extensive order of bony fish, Perciformes, including at least 150 families and more than 6,000 species living both in the sea and in fresh waters. The greatest species diversity is confined to the equatorial and tropical waters, many members have significant commercial value. In the Russian fresh waters widespread are ruff, common perch and walleye, which has the greatest commercial value. In the Black Sea there lives the pilot, a fish that is usually accompanies other larger fish and sometimes marine vessels.
Of certain interest are remora fish, with their head and front part body bearing suctorial disk, making it possible for them to attach themselves to large marine animals and vessels and thus to move over long distances. The archerfish from t fresh waters of tropical Asia feeds on terrestrial insects, whom it knocks down by a strong jet of water ejected from the mouth. Belonging here is also the sea dragon, which is one of the most poisonous fish in the Black Sea. Among the valuable species are the tuna fish, such as tuna, mackerel and bonito.
Among Antarctic fish are the shad-squam and mackerel icefish. Freshwater labyrinth fish live in the warm oxygen-poor waters and can breathe atmospheric air thanks to a special suprabranchial organ. The bullhead widely distributed in fresh and brackish waters have the suction cup formed by fused pelvic fins, with which they can attach themselves to the substrate.
Unlike percoid fish, the scorpionfish are mostly marine inhabitants. Their heads are often armed with spines, and some species have venom glands at the base of spines. In the tropical brigandine gurnard and in the Far Eastern marine chanterelles, the body is protected by a kind of shields.
This part of the exhibit is finished with the flatfish, the anglerfish and the tetraodontiformes fish. Flatfish is a well-known marine benthic fish with a strongly flattened body, one side of which is functionally transformed into the lower part and the other is transformed into the top part bearing both eyes. Interestingly, this is a rare example of vertebrate animals with seriously disrupted bilateral symmetry. Sighted (top) side of the body is more or less brightly colored, with many species being able to change rapidly its color depending on the color of the bottom. Many flatfish belong to the category of commercial species.
Tetraodontiformes are inhabitants of the tropical and subtropical waters of the World Ocean. These fish have teeth in the upper and lower jaws of a small mouth fused together to form a cutting blade. In some species, there is an air bag that is used to inflate body when it is being filled with water or air. The scaled cover is modified and is presented by bony plates, spikes, needles or small spines. Many members (for example, Tetraodon) are poisonous.
The anglers are marine predating fish. The first ray of their spiny dorsal fin is moved to the upper jaw and turned into a kind of rod bearing the bait at its end, which serves to attract prey. Deep-water forms are characterized by strongly pronounced sexual dimorphism; some species have parasitic dwarf males, which are attached to the body of the female. The parasitic male has a blood system fused with that of female, so it is actually fed by female and its digestive system is reduced.