Our planet is inhabited by almost 20 thousand species of fish. About 1/10 of them are commercial. They give people a lot of valuable products: food, medicines, fertilizers for the agriculture, pet food, industrial oils, raw materials for light industry.
To move in the water, have to spend a lot of energy. Nature took care of the fish, giving their bodies zaradougou streamlined shape. The speed of the fish (scombridae, tuna, sharks) in its form and speed resemble that of a torpedo. The fastest fish is considered fish-sailfish, swordfish and Marlin, which reach speeds of up to 130 km/ h. The rate of freshwater fishes is typically lower, but in critical moments of his life, in the moment of impending danger or in the event of an attack on their prey, they can take a short term shot at a speed of 1-2 km /h. Good speed swimmers usually are found in rivers with current (sabrefish, Chub, nase, Dace, salmon). The speed of the fishes living in stagnant water far below, but they are more nimble, nimble (carp, bream, Rudd). Continue reading
The ocean abounds with excellent swimmers who, in the words of the famous German nineteenth-century biologist Ernest Haeckel, “free to find their own way”. They can resist the strong current of water and to choose their own way, different from the animals of the plankton. The combination of these actively swimming animals E. Haeckel called the nekton, which means “floating”. Technically, the nekton are aquatic snakes, birds, and animals, but here we will talk only about the two groups of nektonic organisms — the fish and cephalopod molluscs.
Important nektonic animals adaptations to life in the water column of the ocean, according to Professor Yuri Aleev are maintaining the body in a suspended state, creating a driving force, reducing the resistance of the counter flow of water, control the movement of the body, as well as in the ability to disguise and protection. Continue reading
The difference between marine aquarium from freshwater counterpart in the unusual used items, decorative designs and the tank contents with salt water. It requires the use of more expensive technologies and consumables, and care for marine fish is different from the techniques used in the cultivation of freshwater fish.
If you do not have sufficient knowledge and want to try your hand at a new hobby, then buy an aquarium for small fish is the most affordable and simple type of home decoration, make the room individuality and originality. A reef tank takes the opposite position – this is the most luxurious and time-consuming design, requires constant monitoring, studying Biosystems. In such aquariums it is customary to settle invertebrates, live corals, and large fish then act as predators (eating other inhabitants, and heavily pollute the water).
If you like watching life of predators, populate your aquarium large fish and place it in an appropriate style. There are mixed types of marine aquariums, in which in one area can be accommodated representatives of several subspecies. Continue reading