Types and Description of Freshwater Snails
Freshwater snails are often given a hard time, they are mostly considered as a pest in the aquariums and eradicated before the keepers have had the chance to take a close look at them and take in their own natural beauty. They are a creature that can be beneficial in the aquarium and also in outdoor ponds, they can keep algae levels down and also sift through the substrate releasing any gas pockets. If allowed to get out of control some species do tend to breed quicker than the keeper wishes but this is mostly down to excess food being added to the tank, the snail is an opportunist so over breeding has to be blamed on the keeper themselves.
They are very peaceful creatures, going about their business all day without bothering other tank mates, cleaning the tank which means less tank maintenance is required, this has to be a good thing!
If you do intend to keep snails in your aquarium it must be remembered that they should never be kept with aggressive tank mates and certainly never kept with fish species renowned for making a meal of them such as the Botia species.
All of the different species will have different requirements, some will grow larger than others but generally all of the species do like water with a good degree of hardness, this is important for their shell growth and general well being.
It can be difficult to identify some species of snails as they tend to be clumped into various families with no clear orders but more recently they are being looked at more closer and have been re-classified into their own genus making life a lot easier when looking for a certain species of snail to add to your tank.
There are three main groups of snails that are usually kept in aquariums:-
This group of snails includes the well known Apple Snails, these are becoming more and more popular in the aquarium hobby mainly due to the wide variety of colourations that their shells are available to purchase.
These snails are mostly nocturnal, once the aquarium lights go out they will begin to become active, searching for food and some of the species in this group can travel very quickly around the tank. It is best to use a tight fitting lid with these snails as some species in the group can survive out of water and will even lay their eggs above the water line. It is quite common for keepers of open topped aquariums to find their Apple snails on the floor the next day as they fall off the back of the tanks. The Golden Apple Snail (Pomaceae bridgesii) is probably the most well known member of this group, these are also available to purchase with Pearl, Blue and Brown colourations to their shells and each one of these seem to have their own unique personality which many keepers will verify.
These snails have the added advantage of possessing two sets of respiratory organs, namely gills and a primitive lung, this allows them more freedom above and below the waterline, when keeping these it is always advisable to leave a 2-3 inch gap from the water surface to the lid of the tank to allow them to breathe. They breathe by means of a long syphon tube which extends from their bodies up to the water surface and is an amazing sight to see.
Most of these species also reproduce sexually, there are both males and females. To sex these snails you will have to turn them upside down and look at the mantle, the males will have a penis directly in front of their gills and obviously this is not present with the females. Some species lay their eggs above the waterline, others lay their eggs below the waterline, either way the eggs are laid in clumps and normally hatch after 2-3 weeks dependant on the water temperature in the aquarium.
Another popular species in this group is the Ramshorn Snail (Marisa cornuarietis). These snails do have a reputation for being plant eaters and in some cases this can be very true, the shell colourations can vary with the most common being black or red. The Ramshorn Snail is also an avid breeder and can quickly take over the aquarium if they are not kept in check but they do add interest to the tank and they quite often display some amazing colours, mostly their bright red foot.
Members of this genus vary from the Ampullariidae as they do not possess a lung and must remain below the water surface. Included in this group are some of the trapdoor snails, these have the ability to close of their shells by means of a cartilaginous cover that seals them in, protecting them from any form of danger. Some of the species will give birth to live young, they tend to be less prolific with their breeding rate as there are usually more survivors unlike the eggs layers where many of the eggs fall prey to predators in the aquarium or ponds.
They also tend to leave plants alone in the aquarium, feeding from algal deposits they are of a much higher benefit especially in ponds where algae can be as serious problem especially in the warmer seasons. One of the most well known members of this group is the Chinese Mystery Snail, these are found in a variety of shapes and colours and can live for quite a while compared to other snail species.
Nerite snails can easily be recognised by their tear-drop shaped shell. They can inhabit brackish waters as well as saltwater and freshwater. Nearly all of the species in this group have both sexes and all of the species are egg layers. They tend to lay their eggs enclosed in an outer casing to protect them and this has the advantage of a higher success rate of hatching which means that these too can take over an aquarium if not kept in check.
Nerites are usually a lot smaller than the two groups above, they will normally only reach 1 inch in size when adult but they are also available in a vast array of colourations dependant on species.