Sponges are aquatic animals and most species live in the marine environment. But there are also some species that live in fresh water. Sponges live in large quantities and form "communities", in various types of bottoms. Sponge bottoms are at depths of 30-40 m. With this term, they indicate those bottoms where marketable sponges (such as Spongia, Hippospongia) live in large quantities.

Sponges grow on hard surfaces, such as rocks, dead corals and shells, which can be in the middle of a sand or seaweed bottom. However, for the creation of this "community", the currents need to be strong and stable enough to ensure the renewal of food.

They have various dimensions, the smallest are 1 mm high, while the largest can reach a height of 2 meters. They vary in color even within individuals of the same species. The prevailing colors are brown, black, red, yellow, purple.

They are simple, multicellular organisms belonging to the phylum (Porifera) - Porophora, and their main characteristic is that their surface is rich in pores. These are openings, inlets and outlets, which help to draw in and expel large amounts of water. It has been calculated that about 2 liters of water per second pass through a medium-sized sponge. The volume of water, which penetrates a sponge, to increase 30 grams, is about one ton of water.

The food of the sponge consists of bacteria, microscopic algae, protozoa, eggs and isolated cells, which are left freely in the water by various plant and animal organisms (planktonic organisms).

The size of its feed is proportional to the diameter of its pores and is of the order of 5 µm. In sponges there are no special organs, as well as a nervous system. Their walls consist of the ectoderm (an outer cell layer), from the endodermis (an inner layer of digestive cells), which are separated by an intermediate cell layer (parenchyma), which contains motile cells (amoeboid cells) that can digest and digest their food by phagocytosis. The sponge is also produced here.

Many elements together create "the skeleton" of the sponge. The endodermis consists of very characteristic cells, the choanocytes. Here a very large part of the sponge's food is retained and then passes into the amoeboid cells, where it is digested.

Sponges have no organs of movement and usually remain attached to one point throughout their life. In some species, however, a minimal movement, a small drag, can be observed. They have no sense organs. However, some species show a slight sensitivity to light and touch. However, it has not been proven whether this is due to the properties of the "neural type" cells or generally to the properties of all cells in the body.

Their lifespan can reach 40 years. Inside the channels and pores of their bodies, small marine organisms, such as small crabs, worms, find shelter, for this reason sponges are also known as "biological hotels". Sponges have no predators. Only a few gastropods feed on them. But immediately after the "attack" their regeneration begins again. They are capable of reproducing by direct division or by the formation of eggs and sperm. Sponges are divided into "wild" and "tame" in commercial and non-commercial.