▷ Snails in the Aquarium | All information and details

General information about snails in the aquarium (freshwater/freshwater)

Snails fulfill an important task in the aquarium, they eliminate what is left behind; Food leftovers, dead plant parts and the deceased of our fosterlings. Some species, with more or less great success, also attack the ubiquitous algae.

Zoology:

Snails (gastropods = abdominal feet) belong to the animal phylum of the molluscs. The mollusks also include, for example, mussels, squid and octopus (squid and octopus are also commonly referred to as cuttlefish). With a few exceptions, snails inhabit almost all habitats on earth. The number of species sometimes varies widely. Most estimates assume around 100,000 species.

There are pure herbivores, scavengers, and predatory species. The snails use a rasping tongue, the radula, to feed. This rasp tongue is covered with a large number of small, uniform teeth. This means that the smallest pieces of food are reeled off and swallowed. This process can be observed very well in the aquarium when a snail crawls along the front pane and rasps off the algae coating there with its rasping tongue. The shape, number and arrangement of the rasp teeth on the radula can serve as an important feature in determining the species.

Many freshwater snail species and terrestrial pulmonary snails are hermaphrodites. In the case of land snails and freshwater snails, small young snails, which already have a shell, hatch from the eggs. Veliger larvae hatch from the eggs of many sea snails. These swim around freely for a while, cilia (cilia) are used for locomotion and nutrition.
The snail shell, the shell, consists essentially of lime (calcium carbonate). In the shell-bearing terrestrial snails, this shell provides protection against predators as well as important protection against dehydration. As a further protection, some snail species form a shell cover (operculum), which closes the shell tightly when the animal pulls back into it. In particular, the housing is the most important determining feature, along with the size, color, design, number of windings and winding direction. But the lid of the shell, the operculum, is also an attestation feature. In most snails, the shell rotates to the right. It is very rare for a right-handed species to have animals with a left-handed shell, these are called snail kings.

Some snail species are intermediate hosts for certain parasites (examples):
Large liver fluke – dwarf mud snail (Lymnea trunctula)
Small liver fluke – various land snail species
Paired leeches (schistosomiasis/bilharzia) – various freshwater snails

Snails in the aquarium

As mentioned at the beginning, snails fulfill a very important task in the aquarium. However, some species can quickly become a nuisance. The reproduction rate of some species is enormous. This is probably the main reason why some aquarists reject snails in the aquarium.

Anyone who does not want to do without snails in the aquarium, but on the other hand does not want to deal with a plague in the form of mass reproduction, can certainly be happy by selecting suitable species.

Breeding species

Bubble snails (spring bubble snail, Physis fontinalis):
You often get these as a free supplement when you buy new aquatic plants.

Do snails eat fish eggs?

It is not possible to make a general statement as to whether snails eat the eggs of fish. Especially since precise observation is difficult.

Basically, snails will go at just about anything slower than them. In any case, snails graze on the eggs. This keeps the eggs clean and apparently even prevents the eggs from becoming moldy.
It is difficult to say whether they do no damage to the eggs themselves, whether they accidentally damage eggs, whether they deliberately eat eggs or the contents, or whether they only eat unfertilized eggs.

There have been reports of fish eggs actually being eaten by certain species of snails, as well as reports of no egg being eaten even though the same species of snails had grazed the surface of fish eggs.

Snail species apparently observed eating fish eggs:

However, these reports can be misinterpreted. The spawn is often not examined more closely until a snail has grazed on it. You may only notice dead eggs that had already died before.

Can snails smell?

Again and again it can be observed that snails collect at certain points on the water surface, crawl up the panes after the fish have been fed or collect on the tablets shortly after being fed with food tablets.

Snails take in smell and taste via sensory cells that are distributed on the surface of the body. A particularly large number of these sensory cells are located on the antennae and lips. This allows you to locate dead biomass, algae, etc., even if there is a current in the aquarium.

However, the smell of food does not seem to be the only reason why snails move to the feeding station after feeding. For example, if food that floats on the water surface is given frequently, snails seem to learn to connect the opening of the aquarium lid with the feeding.
At least one can observe from time to time that numerous snails crawl to the surface of the water after opening the lid, even if they are not being fed.

Lime for snails

If the water hardness is low, the snail shells can get holes or break if the snails were reared in hard water.

If the stock of fish allows it, a limestone or cuttlebone bowl for birds can help. The stone can be hung in the water or simply stuck into the ground.
Coral chippings are well suited as a substrate for pronounced snail tanks.

The lime (CaCO3) it contains is not water-soluble and therefore cannot be used directly by the snails. The more acidic the water, the more lime is converted into soluble calcium bicarbonate. The same is unstable and breaks down into a calcium ion (Ca2+) and a hydrogen carbonate ion (HCO3-).

Together with the hydrogen carbonate ions, calcium ions increase the proportion of carbonate hardness in the total hardness. Hydrogen carbonate ions alone increase the acid-binding capacity (SBK), also called acid-binding capacity (SBV). What is called carbonate hardness in aquaristics is in reality the acid-binding capacity.

The part of the GH that does not belong to the carbonate hardness, i.e. the non-carbonate hardness, is formed by the Ca and Mg ions, which bring the anions Cl- or SO4-2- as partners, for example through calcium chloride and magnesium sulphate. Gypsum increases the non-carbonate hardness and thus the GH, lime increases the KH and SBK and thus also the GH.

For aquaristic purposes, to put it simply, the calcium ions increase the overall hardness, i.e. they are so-called GH-formers, and the hydrogen carbonate ions increase the carbonate hardness, i.e. they are KH-formers.

Both are ultimately used by the snail to form the shell, in order to be converted back into lime.

The pH value should therefore be checked before using limestone. If the value is > 7, adding a limestone or cuttlebone is unlikely to be successful. By adding CO2, the pH value can be lowered somewhat, thus supporting the conversion described. The carbonate hardness must be monitored regularly.

Additional chemical information

There is a so-called “calcium-carbonic acid balance”:

CaCO3 (solid) + H2O <-> Ca^2+ + HCO3^- + OH^-

HCO3^- + H^+ <-> CO2 + H2O

If CO2 is introduced, the right side of the 2nd equilibrium, the proportion of H^+ (chemically correct H3O^+) increases, the left side of the lower equilibrium. This disturbs the upper equilibrium, H^+ and OH^- become H2O (right side). Since it is an equilibrium, Ca^2+ and HCO3^- must be supplied, CaCO3 dissolves.

This also works at pH>>7, but the concentration of H^+ is << 10^-7 (e.g. 10^-10 at pH=10).

In order to dissolve limescale, you do not need to reduce the pH value with CO2, just keep it at the same value. It may even rise when CO2 is added, and limescale still dissolves.
Because the conversion of lime to calcium bicarbonate occurs through the direct action of the acidic hydrogen ion of the carbonic acid, independently of the pH value of the rest of the aquarium water, the pH value generally falls when CO2 is added. If lime is present – and only then – lime is converted by the carbonic acid that has been dissolved in the meantime and the water hardness/acid-binding capacity increases.

Do snails tolerate nitrite?

Snails tolerate nitrite just as well or badly as fish. The nitrite also migrates through the skin into the tissue of lung-breathing snails.

Do you need snails?

Snails are a useful addition to any aquarium. Snails eat whatever is too much for the fish and will sooner or later pollute the aquarium water. Even some algae are eaten. This includes uneaten food, rotten plant parts, dead fish, etc.
Tower cover snails also rummage through the substrate, which they clean and loosen in the process.

Snails are an important link in breaking down organic matter before bacteria. If snails multiply too much, this is a sign that the aquarium is overloaded. The reason is usually too much food. So they are indirectly a good indicator of whether you are feeding correctly or too much.

At least some snail species can also be intermediate hosts for some parasites.

Snails in an open aquarium

Whether they can be kept in an open tank depends on the species of snail.

Apple snails lay their egg packs outside of the water. To do this, of course, they have to crawl out of the water. They occasionally lose their orientation and climb out of the aquarium instead of crawling back into the water.

Neritinas sometimes climb out of the aquarium too. Mostly they crawl on glass struts or the rim, shit there and crawl back into the water. But sometimes they can’t find their way back.

With apple snails and Neritinas, it makes sense to leave a distance of about 10 to 12 centimeters between the water surface and the edge of the aquarium.

If you are lucky you will find a snail that has climbed out in time. In any case, it is worth putting such a snail in a container with aquarium water first to see whether it recovers.

Housings that are not severely damaged in the event of a fall on the floor can heal again. A crack in the housing is therefore by no means a criterion for hasty disposal of the snail.

snail traps

Snail traps from the aquarium trade are usually designed in such a way that small armored catfish, young…