Snails And Molluscs In The Aquarium

2023 Author: Molly Page | [email protected]. Last modified: 2023-07-31 03:34

The aquariums contain representatives of two classes of mollusks (Mollussa) - bivalves (Buvalvia) and gastropods (Gastropoda).

The body of bivalve molluscs is covered with a hard bivalve shell with a wider anterior and narrower posterior end. The shell is opened by means of an elastic ligament that connects the valves on the dorsal side. The valves are closed with the help of two closure muscles that run across the body at the anterior and posterior ends.

All organs in bivalves are covered with a mantle, which hangs from the sides in the form of two skin folds. Between the folds there is a mantle cavity, in which the body of the mollusk is enclosed. On the abdominal side of the body is a muscular leg, with the help of which the mollusk moves. On the sides of the leg there are two pairs of lamellar gills, at its base there is an oral opening.

Marisa snail (Marisa cornuarietis).

Astrakhan Internet club of aquarists "Golden Oranda"

Of the bivalves, the following representatives usually come across.

Perlovitsa (Unio) is found in rivers and lakes. The shell is broadly oval with biconvex valves. Its color is greenish-brown with dark stripes that run parallel to its outer edge. The color of the mollusk itself is pinkish-white. A shell per day is capable of passing 40 liters of water through itself, while capturing microscopic living creatures and rotting particles with its mouth tentacles.

Toothless (Anodonta) differs from the previous genus in its larger shell. Pearls and toothless in an aquarium are extremely rare, and even then with special chains. The technique of keeping these mollusks is extremely complex and not available to everyone.

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Sharovka (Sphaerium corneum). River snail. The shell is lenticular, brown with a yellowish rim and regular yellow stripes. The mollusk itself is yellowish-gray. The respiratory and anal openings are two fused reddish tubes that protrude from the shell. The eggs develop inside the animal in special bags on the inner side of the gill plates. Digging usually in the silt at the bottom of the aquarium, the ball with a lack of oxygen in the water can rise to the upper layers of the water.

Duck toothless (Anodonta anatina)

Gastropods are more mobile than bivalves. They do not burrow into the ground, but crawl over plants, the bottom and walls of the aquarium. The species listed below have a spiral-wound shell. The ventral side of the body is a broad, muscular leg adapted for crawling. The front ridge of the body - the head of the mollusk - is equipped with two pairs of tentacles.

In freshwater forms, the eyes are located at the base of the second pair of tentacles. In many, the gills are replaced by lungs. Many freshwater gastropods are hermaphrodites; fertilization is internal. The eggs are deposited on the lower surface of the leaves of aquatic plants and on various objects. Development takes place entirely inside the egg shell.

The most common gastropods in aquariums are:

Fiza (Physa fontinalis, Physella acuta). Occurs at the bottom of swamps and ponds, in silt and on underwater objects. It is a small snail (less than 1 cm) with a rounded yellowish-brown shell curled to the left, the leg is black and blue.

Horn coil (Planorbarius corneus)

Physsa can secrete a sticky thread that attaches to plants near the surface and to a rock or plant near the bottom. She uses this thread when going down and up.

Phiza lays testicles in the form of strands on underwater plants. It multiplies very quickly and it is useful to keep it in aquariums with adult fish, as it cleans the plants of algae and eats up the remains of food. In spawning grounds, fiza is harmful. Crawling over the eggs, it breaks their shell, which can lead to the death of developing embryos.

Red physis (Physastra proteus). This species is imported from Australia. In the aquarium it plays the same role as the previous species. Has a red coloration.

Related article Freshwater snails in an aquarium

Horn coil (Planorbarius corneus). It is found in swamps and ponds. The water snail, which has a shell with flattened spirals, is brown and thin. The leg is wide and flat.

In spring it lays eggs in gelatinous heaps on plants and walls of the aquarium. After six weeks, young snails emerge from it. This is a very useful snail, as it cleans the walls of the aquarium and eats up the remains of food.

Common pond snail (Lymnaea stagnalis)

Horn red coil (Planorbis corneus var. Rubra). Red variety. Easily crossed with a horny coil, offspring in the first generation are black. Everything said about Planorbis is also true of her. Requires a higher water temperature (22-24 ° C).

Large pond snail (Lymnaea stagnalis). Found in ponds and swamps. Large, greenish-gray mollusc with yellow spots. The shell is light.

Caviar is deposited in strands on the lower surface of the leaves and on various objects. Young snails emerge from their eggs on the 20-40th day. The pond snail grows very quickly and is very voracious. It eats plants, fish eggs and even fry, so it cannot be kept in spawning grounds and in aquariums with valuable plants. In addition, other gastropods such as Lymnaea auricularia, Lymnaea peregra, Planorbis planorbis, Anisus vortex, Anisus contortus, Gyraulus albus, Segmentina nitida, Valvata piscinalis, Bithynia tentaculata may be accidentally introduced into the aquarium.

In recent years, in the world literature on the issues of aquaristics, there have been references to new gastropods in the aquarium.

Source: "Indoor Aquarium"