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These mollusks are present almost in every freshwater aquarium, they are used to them, they are almost ignored. As a rule, no one specifically targets them and, moreover, does not breed them. But one must think that they are not very concerned: they have found a stable niche in the aquarium ecosystem and are not going to surrender their positions. Grunt - this is their home, shelter, feeding and breeding place. To protect the aquarium from penetration of these animals is difficult, getting rid of the formed population is even more difficult. And it is not necessary: ​​there is no damage from inconspicuous ground inhabitants, but they play a more or less correct role of a kind of live drainage. Of course, you already guessed that we are talking about melanias - small viviparous snails, which in everyday life are called sandy.
Molluscs of the genus Melanoides belong to the Thiaridae family of gastropods (Gastropoda). Previously, they were members of the Thiara family, so those who typically have a Russian version of the Latin transcription of melaniya seem too old-fashioned may resort to using a more romantic name - tiara, especially since in the special literature it is still possible to find this outdated Latin name. But keep in mind that, from the standpoint of modern taxonomy, these genera are completely independent.
The area of ​​melanium is very extensive. They can be found almost throughout Africa - from Morocco to Madagascar, in Asia - from Turkey to Malaysia and Australia. Thanks to the high adaptability of melania, new regions are constantly being mastered: their patrimonies are the southern latitudes of North America, the south of Europe, etc.
In natural conditions, these mollusks inhabit small water reservoirs with a weak current, where they occupy mainly shoals and coastal areas with a depth of up to 1 m, but recorded them at even greater depths - up to 3-4 m. The snails prefer a soft bed consisting of a mixture of silt, sand , Clay sediments. Here they form quite dense settlements. From a square meter of the soil surface, 1,5-2,000 adults can be harvested, and 30-35 thousand mollusks coexist in the "plantations" especially rich in forage on the same area.
The basis of the food ration of melania is composed of inferior algae, half-decomposed organic matter, etc., that is, these snails are typical detritophages. In search of food, they actively scurry along the surface of the bottom and deepen into its thickness, provided that the soil here is rather loose and not compressed by stones and thick interlacing of the roots of higher vegetation.
Unlike most aquarines known to aquarists, melanions breathe with gills, that is they are able to absorb oxygen dissolved in water and do not need periodic raids to the surface of water to capture an air bubble. And they multiply atypically - they are characterized by live birth.
In the aquarium literature, only one species of snails is traditionally mentioned: Melanoides (Oliver, 1804), namely M. tuberculata (Mueller, 1774). But to consider the genus monotypic would be wrong, since in reality it is represented by at least two other species: M.riqueti (Grateloup, 1840), inhabiting the fresh waters of Singapore, and M.granifera (Lamarck, 1822), inhabiting small rivers and streams of the western Parts of Malaysia. In the special literature of these snails can be found under the names Tarebia granifera or Tarebia lateritia.
In addition, there are also Filipino molluscs M.turricula (Leo, 1862), but their systematics has not yet been established: according to morphological features, they are very close to M.tuberculata, and many biologists grant them only the status of subspecies. At the same time, in terms of ecology, these mollusks are different. If M.tuberculata is more common in slow-flowing and standing turbid waters, M.turricula prefer rivers and streams with rapid flow and clear clear water. Guided by this, some experts singled out these snails as an independent species.
Melanias of all kinds have a conical (turbo-spiral) shell, the mouth of which can be tightly closed with a lime cap. This peculiar door allows the snail to escape from enemies, and in addition, for a long time to maintain the necessary microclimate inside the shell and in this way for a fairly long time to tolerate adverse changes in the environment. But even without this protective mechanism, the viability of melanium is very high. They can withstand a wide range of temperatures (from 18 to 28 degrees Celsius), salinity (up to 20 ppm), are practically indifferent to the rigidity of water, its active reaction, and other chemical parameters.
Perhaps the only factor that is of fundamental importance for melanics is the concentration of dissolved oxygen. With its lack of shellfish leave the ground and rush closer to the surface.
Lovers often deal with M.tuberculata. Snails of this species have long been habitable aquariums and are hardly an integral part of the ecosystem of decorative indoor ponds. It is hardly possible to follow the history of their penetration into culture thoroughly. Most likely this happened spontaneously and they were brought together with plants from some Asian or African water body. The same way melanii usually migrate from one aquarium to another. To impede such migration is very problematic: it is very difficult to discern (even with the help of a magnifying glass) new melanions in the thick of a powerful bundle of roots of a particular aquatic plant.
Even harder to find them in the mass of gravel or pebbles. To guarantee the release of soil from shellfish, radical measures such as calcining or boiling are required, and it is not always possible to implement them, at least if it is a question of large volumes. Fortunately, situations that dictate the need for such tantalizing activities are extremely rare.
The shell in M. tuberculata is elongated, acute-conical, with a diameter in the widest part - near the mouth - about 5-7 and 30-35 mm in length (in the literature there are references to giants up to 7-8 cm in length).
The main color is gray with an admixture in various proportions of greenish, olive, brownish tones.
Curls of the spiral of the shell at the mouth are wider and more contrasting. They are clearly visible reddish brown strokes, oriented, as a rule, parallel to the axis of the shell. The length, width, color of the strokes and the nature of the pattern they form are individual. Occasionally snails are found, in which the color of one or two of the first curls is fundamentally different from that of the others; They look very decorative, especially when it comes to a combination of dark and light fields.
It should, however, be noted that with a moderate number of snails, satisfactory permeability of soil and its normal ventilation, you can not admire M.tuberculata in an illuminated aquarium. It's not that they are fearful, but still at the first opportunity they strive to burrow into the ground. The rate of immersion depends on the structure of the ground: the smaller the particle, the faster melanya disappears from the eyes.
By the way, the opinion that these snails without soil can live a few hours, is greatly exaggerated.
Somehow for the sake of experiment, I put a couple of melanions in a vigorous aquarium, where besides the necessary equipment, a bunch of plastic echinodorus and several dozen fry more were nothing. He noted the date of landing in the diary and waited (let them forgive me for being "green") of this most inevitable death of mollusks. At first, they controlled their condition almost hourly, then the bill went for a day, a week.
On the twenty-third day it happened ... No, not at all what I was waiting for: instead of, according to the instructions in the literature on aquaristics, quietly moving into a different world, sand snails made themselves similar - tiny (a little more than a millimeter) cubs in the number 5 Pieces.
I can not say that melanions are born just like that. I fully admit that their appearance was held a few days earlier and I simply did not pay attention to these subtle creatures (especially since I did not seek them, tuning in to the diametrically opposite results of the experiment).
Melanes grow slowly enough. For a month they added to the starting length of 5 - 6 mm (for comparison: coils for the same period become almost adults). Perhaps, in the rich detrital soil, their development goes faster.
In recent years in Russian aquariums "registered" Melanie another species M.granifera. In my opinion, they look more attractive and harmonious than their relatives. Their domed shell, painted in saturated gray-brown tones, is composed more proportionally: the height of its cone is less (up to 2 cm), and the diameter is larger (1.0 - 1.5 cm). The old broad curls have a slightly corrugated structure with light, almost white peaks and dark depressions. Probably, this figure also determined the choice of the Latin name of the species, which literally means "dragging grains". In the English literature, it is referred to as "Quilted melania" - that is, patchwork, or quilted.
The habits of the granite are somewhat different from their popular counterparts. They are more thermophilic, more capricious with respect to the composition of the soil and at the same time somewhat less attached to it. Ideal for them is the soil fraction of 1 - 2 mm, that is, large sand. In a ground consisting of more massive and heavy particles, it is difficult for these snails to push their wide shell. But M.granifera spend more time in sight, concentrating on driftwood and large stones. And if the appearance of ordinary melanium on the walls of the aquarium, decorations, plants indicates a poor climate in the lower horizons of the reservoir, then this feature does not work for M.granifera.
In comparison with M.tuberculata, the granites are more sluggish. This applies both to the speed of movement, and to the rates of adaptation and reproduction.
The population of M.tuberculata develops rapidly. It is enough to get into the aquarium a pair of adult mollusks (they have parthenogenetic reproduction, which requires the presence of a partner), as in a month or two more snails can be fixed in dozens. In order to achieve a similar density of the population, the granitors will need at least 6 to 8 months.
There is one more difference. If the usual melanions are evenly distributed throughout the soil, the granites form certain local communities, concentrated on certain parts of the bottom. For example, in my aquarium they are muffled mostly near the bottom of the feeder. Perhaps this is due to the fact that almost always there are plenty of unclaimed fish particles in abundance, and in other places the sluggish granaries are not able to compete in food terms with the "quick" M. tuberculata. Nevertheless, both species get along well in one home pond. In other, and in natural conditions, their areals often overlap.
I think that the granite has good prospects to become one of the most popular objects of a decorative aquarium. Here, for sure, the external appeal of these mollusks and the measured, unhurried way of their life will play their role. After all, the number of ordinary melanies, if not regularly caught by large individuals, grows exponentially, and, in the end, the soil begins to literally move from the abundance of snails inhabiting it. And the granites will gradually master the lower horizons of the indoor reservoir, doing their good deed and at the same time not bothering the aquarist with his obsessive redundancy.


V. Safronov Moscow, Aquarium No. 3, 2001.