Atkritumu fish. One dorsal fin. Pelvic fins located on the belly. In the pectoral fins and in most species the dorsal fin is spiny, often jagged rays. Non-rising mouth surrounded by tendrils. The jaws teeth. Body naked or covered with bony plates. Many have an adipose fin.
The inhabitants of the mainly tropical and subtropical freshwaters of South and Central America, Africa and Asia.
The squad consists of 20-30 families and over 1,200 species. 2 family of marine fish.
The Catfish Family – Siluridae
Body naked, elongated. Adipose fin not. The head is flattened, the mouth large, polverini. Dorsal fin short (not more than 5 rays). Anal fin long, not less than 70 rays. These freshwater and brackish-water predatory fish with spring and summer spawning. They live in fresh water in Europe and Asia, in addition to the basin of the Arctic ocean.
The family includes 8 genera, 2 of which are found in our country.
Rod Catfish – Silurus. Antennae 3 pairs. Thorn in the pectoral fin is smooth.
The genus includes 2 species.
Com S. glanis Linne, 1758. Front mandibular barbels shorter than the back. Spiny rays of the pectoral fin is strong (Fig. 110, 1). Reaches a length of 5 m. of residential Forms and the checkpoint form. These fish developed to take care of offspring. Soma build primitive nests from vegetation remnants.Inhabit the waterways of Europe: the Rhine, North to South Finland, and South to Asia Minor. Continue reading
The first thing we need to think about is the size of your aquarium. Much easier to maintain in good condition a large volume of sea water than small. The minimum size of marine aquarium should be 100 x 50 x 50 cm the larger the aquarium you can afford, the better.
Technically, the organization of the aquarium with sea or brackish water is absolutely the same as freshwater. The main difference is only that in water you need to add salt. Since this water is in increasingly corrosive than freshwater, aquarium eliminated any metal objects. The destruction of the metal in the water can lead to poisoning of fish.
All items used for preparation of water and irrigation of the soil (buckets, colanders, spoons etc.), should be plastic. If you have an external thermostat, stick them to the glass and do not hang on the wall of the aquarium with the help of metal hooks with which they are sold. The same applies to the combined instrument heater-thermostat Even fixing of luminescent lamps to the cover must be non-metallic.
For most of us to use clean seawater is not possible, because either we live too far from the sea, or the seawater is heavily polluted. Manufacturers produce salt for sostoyatelnoy sea water with the right balance of minerals that the fish need. You just have to mix the salt with tap water in accordance with instructions to obtain the required specific gravity of the final solution. Continue reading
Fish are cold blooded animals i.e. their body temperature is close to ambient temperature and does not exceed it by more than 0.5. 1 deg. So the speed of metabolism they depend on the water temperature. Only tuna as a result of intensive muscular activity in rapid motion the body temperature may exceed the temperature of water at 10 deg.
From vertebrate fish – the largest group of animals. There are over 20 thousand species – more than the amphibians, reptiles, birds and mammals combined. In the superclass of Jawed (Gnathostomata), which include all fish, from 515 to 550 species belongs to the class of Cartilaginous fish (Chondrichthyes) (chimeras, sharks, rays) and from 19135 until 20980 species to the class of Bony fish (Osteichthyes) (all other fishes, including cartilaginous ganoids – sturgeon and others, which in the adult skeleton presents no spine, and the chord, but there are also bones, mainly covering forming the outer skeleton). In addition, there are about 50 species of lampreys and mixin-jawless fish-like animals, which fish are not. They come in the Cyclostomes (Cyclostomata), belonging to another superclass – Jawless (Agnatha), though are together with fish for the same type of Chordates (Chordata) and subtype Vertebrates (Vertebrata), or Skull (Craniata). About 41.2% of fish are typically freshwater, about 0.6% live in both fresh and salt water (brackish). The remaining 52.2 per cent is marine fish, of which 39.9 per cent live in the coastal waters of warm seas and oceans, 5,6% – in cold coastal waters, 6,4% are deep-sea bottom and bottom-dwelling (benthic) species, 5% of deep-sea pelagic and 1.3% live far from the coast in the upper 200 m of the water column of seas and oceans (epipelagic species). Continue reading