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
Before you start seahorses, carefully familiarize yourself with the basic rules of care.
Often aquarists are looking for a small ecosystem of some unusual animals. We like to add to their aquariums animals with vivid coloration, unusual behavior, or freakish body shape. No animals do not fit this description better than seahorses. Seahorses – the holders of the truly mythical body shape: consobrina head is wonderfully combined with the reinforced, curved body. These are truly fantastic creatures are very interesting to watch, but if you prepare properly in advance, then keep them in an aquarium is no more difficult than any other fish. Today I will try to dispel some myths about the seahorses, common among aquarists, as well as talk about the basic requirements for creating a suitable for seahorses environment, so that even the beginners had the opportunity to watch these amazingly beautiful animals at home. Continue reading