This article covers the basic information about snails and will interest aquarists having snail problems in their fish tank or would like to keep snails just like any other aquatic pet. Before we get into details of keeping/removing snails from tank, it is useful to understand their habitats and reproduction method.

General information: There are more than 80,000 species of snails identified till now on earth, 55,000 of which are marine species. The remaining 25,000 either live in freshwater or on lands. The most common aquarium snail is Apple snail.

Evolution: Snails first evolved in marine habitats and later expanded into freshwater and terrestrial habitats.
Lifespan: The lifespan of snails varies from species to species. While some snails can live up to 30 years, aquatic Apple Snails live only about a year.
Food habitat: Snails eat plankton, algae, microscopic organisms, decaying plants, decomposing flesh of dead animals.

Body construction: The body or shell of the snail is largely made of calcium carbonate. Snail need calcium to construct its body. The acidic water tends to dissolve the shell, so snails prefer hard and more alkaline water. Most snail shells are right-handed, meaning that if the shell is held with the apex (the tip, or the juvenile whorls) pointing towards the observer, the spiral proceeds in a clockwise direction from the apex to the opening.

Reproduction: All land snails are hermaphrodites, which means, each snail has both male and female parts. They still must mate to reproduce, however. A hole near the head is the genital orifice where the snail mates and also from where it lays its eggs. Some freshwater snails (example apple snails), and marine species (example periwinkles) have separate sexes, they are male and female. The age of sexual maturity is variable depending on species of snail, ranging from as little as 6 weeks to 5 years. Aquatic snails have both hermaphroditic and heterosexual reproduction. Most snails lay eggs; however a notable exception to this is the Malaysian Trumpet Snail, which is a live-bearer.

Freshwater Aquarium snail: Apple snails are popular aquarium-pets because of their attractive appearance and size. When properly cared for, some apple snail species can reach 15 cm / 6 inch diameter. Apple snails are in fact the biggest living freshwater snails on earth.
Water snails breathe through gills whereas land snails breathe through a hole in their body near the base of the shell.

Advantages of aquarium snails:
• As snails eat algae and decomposing flesh, they eat up all un eaten food in the aquarium and keep your aquarium clean. Snails are better algae eater than algae eating catfish because, snails can reach each and every corner of your aquarium (behind the rocks, caves etc.) which catfish cant.
• Snails eat decaying plants so reduces the maintenance of a planted tank and improves water chemistry. Please remember few pond snail will eat plant and can destroy your planted aquarium so be careful while selecting snail species for your aquarium.
• In a breeding tank, the eggs on the substrate are in great danger from predators. If you have algae eating catfish, it will eat these eggs whereas snails are less likely to eat them.
• Few snails are very attractive (example: Mystery Snail) which you can keep as aquarium pet.

Disadvantages of snails
• If you don’t control their number, snails can quickly multiply exponentially which will spoil the beauty of your aquarium.
• A large number of snails in a tank can upset its ecological balance.

How to remove snails from aquarium: If you are not happy with snails in your aquarium, you can remove them completely or reduce their growth in many ways. I have categorised the below options according to my preference but you can decide which is more suitable for your tank and your situation.

Option 1: Remove them manually: I personally use this method because there is no side effect of this on your tank. One of the easiest methods is to take some lettuce or green peas, wash them with hot water, keep them in a glass jar or pot and leave the pot over night (switch off the tank lights). Snails will stick to the lettuce for food and you can remove the pot next morning. You can attach a string to the pot/glass for easy removal of the jar without putting your hand. No doubt you can’t remove them all and you have to repeat this process to control their count on your tank. If you have lot of plants in the tank, the lettuce may not be very attractive to the snails and have poor results. In that case the only option it siphon them while you are doing a partial water change.

Option 2: Control feeding: As the snail live on uneaten fish food in your tank, reducing food quantity will reduce their count/growth. Feed your fish such that they can eat them in less than 5 minutes. Remove uneaten food from the tank. For more details read the article on feeding your aquarium fish. (http://aquariumhomecare.com/modules/AMS/article.php?storyid=5)

Option 3: Add snail eater or predator: add few snail eaters (ex. Clown loach, Puffer) to your tank they will eat your snails and keep their count under control. The only problem with this method is, Clown loach are schooling fish so you should keep 6 or more in a tank. Puffer fish are aggressive and not suitable for smaller fish.

Option 4: Adding Aquarium Salt: when you add salt (NaCl) to your aquarium, the salt concentration changes and since the snails (or other pathogens, such as bacteria and protozoa) are simpler forms of life that have no internal organs to compensate for the change in salt concentration they die but not the fish.Fish have organs, such as kidneys, that enable them to adjust to a small change. Please do not use table salt to get rid of snails in your aquarium because the table salt is prepared for human consumption and contains a small amount of iodine and calcium silicate. Though few people have used table salt without loosing any fish it’s not recommended for aquarium. Use Aquarium salt which has no added iodine or calcium silicate

Option 5: Use Snail-Killing commercial chemicals: there are many commercial chemical products available at aquarium stores. If used as instructed, it may kill all your snails in one go, but there are few disadvantages with this method. It will kill your useful bacteria which are responsible for Nitrogen Cycle in your tank. Since this will kill all the snails in one go there will be lot of dead animals creating more ammonia or nitrite but with not enough bacteria to decompose them. As a result you may get ammonia or Nitrite spike on your aquarium. If you go for this option, do a 5% water change every day for 15 days. Test and monitor Ammonia & nitrite level during this period.

Prevention: If you don’t like or want snail in your aquarium then the best way to avoid snail problems is never allow them to get into your tank. Snails usually come to your tank as grown snails or egg. Most common media of transport are plants where snail or eggs are attached to the leaves. Some time they also come with the fish from your local fish store. As described above all you need is one snail or egg to start the battle.

Care while adding Fish: It is advisable to net the fish and discard the water to avoid transmission of any snail (including eggs) or any other parasite to your tank.

Care while adding plant: take extra care while adding plants. Visually inspect them that none of the plant leaf has eggs or snails on it, If you find any eggs or snails then remove them before adding to your tank. You can also wash or soak the plant with following

Treat plants with low concentration of aquarium salt: Add a half table spoon of aquarium salt in a 2 litre mug of water. Soak the plants in this salt solution for 5 minutes and wash them with fresh water before adding them to tank.

Treat plants with low concentration of Alum: add a table spoon of alum to a 2 litre mug of water. Soak the plants in this alum treated water for 24 hours and then wash them with fresh water before adding them to tank.

Treat plants with Bleach or chlorine: This is probably the most effective way of removing snails or eggs from the plants. Add a half cup of bleach in a 2 litre mug of water. Soak the plants in this solution for 5 minutes, then soak for another 5 minutes in water with de-chlorinating agent and finally wash them with fresh water before adding them to the tank. Please note, bleach may damage the sensitive plants so please read about the specific plant species before treating them with chlorine or bleach.

Treat plants with Potassium Permanganate (KMnO4): add one-fourth table spoon of potassium permanganate to a 2 litre mug of water. Soak the plants in this solution for 15 minutes and then wash it with fresh water before adding them to tank.

Hope you will find this article useful.

Good Luck

Deepak
[I Love My Fish Tank]


Reference:

Wikipedia: Snails
Wikipedia: Apple Snails
Aquarticle: aquatic snails
Structure of a Snail Shell