Anyone who has been involved with aquarium keeping is probably familiar with snails at one level or another. To some aquarists, they are valued algae eaters and scavengers that help clean the tank and keep things in balance. To others, they are a loathed scourge that quickly overrun the tank and are close to impossible to get rid of, and to some, they are beautiful creatures that make colorful, interesting pets.
For the most part, freshwater aquatic snails are hardy creatures that thrive in the same water parameters as most aquarium fish, making them easy to keep and compatible with a wide variety of fish and invertebrate species. They come in a variety of sizes and colors, and despite popular belief, not all snails are prolific breeders that will overpopulate your aquarium, although a few types can and do. Always research any new additions before introducing them to your tank. In this article, we will look at the different types of freshwater snails and how to properly care for or avoid them.
Good Vs. Bad Snails
There is a tendency to categorize aquarium snails as "good" or "bad". Truth is, all snails are good for our aquariums in one way or another, it's just that sometimes they do things we do not like or are unprepared for, like eating our plants or overpopulating the tank. Virtually all problems with snails can be avoided by understanding them, knowing how to avoid accidentally introducing them to your tank and doing adequate research to make sure you buy the right snails for your aquarium.
"Good" Aquarium Snails
Most aquatic snails are great at getting rid of algae and consuming uneaten food, dead plant matter and other detritus that accumulates in the aquarium. One type, the Malaysian Trumpet Snail (MTS), burrows in the sand or gravel looking for food, and in doing so, they keep the substrate clean and prevent it from compacting and becoming anaerobic. Sadly, they are also the primary culprit for overpopulating an aquarium.
More recently, aquarists seek snails as unique pets. Their bright colors, intricate patterns and unusual shapes make several snail species ideal candidates for aquariums of all types and sizes.
"Bad" Aquarium Snails
There really are no "bad" snails, but a few species can multiply unchecked and overrun an aquarium. Seeing hundreds, if not thousands of these little beasts taking over your tank can be unnerving, and they can place a burden on biological filtration as well as clog filter intake tubes. Malaysian Trumpet Snails (MTS) and ramshorn snails are prone to doing this. To add to the problem, nuisance snails are virtually impossible to eradicate once they are in your aquarium. Ironically, one way of dealing with unwanted snail outbreaks is to introduce a species of snail that eats other snails! This article will touch more on this below.
Some species of apple snails (Pomacea) are voracious herbivores that will decimate a planted aquarium in short order. Apple snails have also caused damage to crops in certain parts of the world after being inadvertently introduced into the wild. However, the majority of apple snails in the aquarium industry make great aquarium scavengers and usually leave plants alone.
How Do I Get Snails In My Aquarium?
There is only one way snails get into our aquariums – we put them there. But, you might say, I've never purchased a snail in my life and suddenly they are showing up! The most common ways unwanted snails enter our aquariums accidentally are via eggs or juveniles hitchhiking on plants or decorations, or in gravel cultures transferred from one tank to another.
Many snail eggs are transparent and are often attached to the undersides of plant leaves, making them difficult to see. Juveniles of red ramshorns and pond snails can be very tiny and hide easily, especially in fine-leaved plants. There are ways of eliminating snails and their eggs which will also be discussed below.
Malaysian Trumpet snails are often transferred in used gravel intended to help start the biological cycle in a new aquarium, but they can come in on rocks, plants, driftwood and decorations, as well. MTS are known to live in buckets of used gravel for over a year! Even after rinsing the gravel thoroughly, they can still be alive and well, ready to start reproducing in their new home.
Types of Snails
Sometimes called Inca snails, Mystery snails (Pomacea spp.) are a type of apple snail and are among the most popular in the aquarium hobby. These peaceful snails live 3 to 4 years, grow to a little over 1½ inch in diameter and are valued for their bright colors and algae eating ability. Bodies are usually black or pinkish-orange with neon orange spots around the head area. Shells can be tan or olive with dark stripes, maroon, white, golden yellow or blue. They eat soft algae, dead plant matter and make great scavengers in peaceful community tanks.
There are several theories about how Mystery snails got their name, but a popular one is that when they were first introduced into the hobby, no one knew what kind of snail they were; it was a mystery. Scientists have described two species popular in the aquarium industry – Pomacea bridgesii and Pomacea diffusa, with P. diffusa thought to be the most common one.
Mystery snails have gills as well as a lung, with a sort of siphon tube that allows them to breathe air by coming to the surface. A secure lid should be used to prevent them from climbing out of the tank. Breeding is not difficult; mystery snails are gonochoristic, meaning you need a boy and a girl for it to happen. In addition, the female must be able to leave the water to deposit her eggs, which appear as a honeycomb-like cluster on the tank wall above the water line or attached to the underside of the lid. Babies hatch out in 2 to 3 weeks, depending on temperature, and drop into the water.
Nerites (Neritina spp.) are fantastic algae eaters that also eat leftover fish food, dead plant matter and other "stuff" that ends up on the bottom. They come in different colors and patterns, including one with horns! They are among the most beautiful of all aquarium snails. They are relatively small, they don't eat plants and their waste contains bacteria that is beneficial to the digestive tracts of shrimp, making them perfect for planted aquariums and shrimp tanks.
Nerite snails are not difficult to breed, but the larvae require brackish or saltwater to develop, so there is little risk of them overrunning an aquarium. They are thought to live at least 3 years, but there are reports of 5 years from hobbyists. They love to crawl out of the water, so make sure you have a secure lid on your tank!
A relatively recent addition to the hobby, Rabbit snails (Tylomelania spp.), are rapidly becoming an aquarium favorite due to their larger size, interesting colors and "rabbit-like" faces. Native to Sulawesi, Indonesia, some species can grow up to 4 inches in length, and they are thought to live up to 3 years. They do best in aquariums of 20 gallons or larger and prefer warmer temperatures (76° - 84°F) and slightly alkaline water with pH 7.8 – 8.4. Some aquarists mix crushed coral into the gravel or place coral in their filters to achieve the correct water chemistry.
Rabbit snails feed on soft algae, dead plant matter and other detritus, but they will also eat sinking pellets, algae wafers and other fish foods that fall to the bottom. They do not bother plants, however, there are anecdotal reports of them nibbling on Java Fern.
Rabbit snails are gonochoristic and give birth to live, fully developed young, that are enclosed in a milky white egg pod. Babies are usually born one at a time, although occasionally two or even three are encased. Egg pods are produced once every 4 to 6 weeks, so their reproductive rate is very slow, even if you have several of them.
Assassin snails (Clea helena) are native to southeast Asia. They have become popular in the
aquarium because they eat other snails, making them a natural method for reducing nuisance snail populations. They grow to about 1 inch in length and have alternating yellow and dark brown "bumble bee" stripes. They like to burrow in the substrate but quickly come out for food.
Unlike most aquarium snails, which are largely herbivorous or at least omnivorous, Assassin snails are carnivores, feeding largely on other snails or carrion. However, they will not eat their own kind even when other food is in short supply. A few shrimp breeders have reported seeing Assassin snails eating their valuable shrimp, but experts believe that this happens very rarely, and the victims are most likely weak or sickly.
Assassin snails are known to breed in captivity. They are gonochoristic, so if you want to breed them, you should start with at least 5 or 6 to make sure you have males and females. Reproduction is slow because females only lay 1 to 4 eggs at a time. Eggs are transparent and difficult to see, hatching out in 8 to 9 weeks, depending on temperature.
Ramshorn snails have been in the aquarium hobby longer than almost any other type of snail. Some aquarists use them to help keep fry-rearing or shrimp tanks clean, while others consider them a pest that should be eliminated at any cost. They are great at eating soft algae, dead plant matter and leftover food, but they can multiply quickly, especially in aquariums that have a lot of organic debris. They are also known to eat soft-leafed plants when food is scarce.
The two most common species in the aquarium trade are, the Red Ramshorn and Planorbarius corneus, a larger species known as the Great Ramshorn. Red Ramshorns are red, as their name suggests, while Great Ramshorns are typically olive-yellow to brown, with stripes on the shell. Other variants, such as pink, yellow or blue are also available. Ramshorns are air-breathers, making it necessary for them to come to the surface to breathe.
Great Ramshorn snails are usually introduced intentionally into aquariums to control algae and help keep the tank clean, but Red Ramshorns often appear spontaneously. More often than not, tiny individuals or eggs sneak in on live plants, rocks, driftwood, ornaments and even gravel transferred from one aquarium to another. A sudden population explosion is often a result of detritus and organic waste building up in the aquarium.
Malaysian Trumpet Snails
When it comes to multiplying, the Malaysian Trumpet Snail (MTS), Melanoides tuburculata, has few rivals. Depending on your outlook, these small, cone-shaped snails can be the best scavenger known to aquarium keeping or the most despised creature on earth. To be sure, they are prolific. They are parthenogenetic – not hermaphroditic – meaning females can give birth to more females without requiring contact with a male. In short, one tiny hitch-hiking female is all it takes to get things going, and they are virtually impossible to get rid of once they enter your aquarium.
On the positive side, MTS forage in the substrate by day, keeping it aerated and breaking down any organic debris and waste that accumulates there, preventing anaerobic conditions which can release deadly hydrogen sulfide gas from developing. Plus, they won't eat your plants. For these reasons, they make excellent scavengers for planted aquariums, shrimp tanks and aquariums that are heavily stocked or fed generously. That is comforting if you like natural methods, but for some folks, seeing that many snails in a tank or watching your gravel actually "move" is, well……. a little creepy.
It is pretty much impossible to eradicate MTS entirely once they are in your aquarium but cutting back on feeding and vacuuming the substrate regularly will deprive these snails of their food source and keep their numbers down.
Several species fall under the term "pond snails". To some hobbyists they are a valued scavenger, while others consider them a pest. Most grow to an inch or less and are olive-green to speckled brown in color. They are omnivores, feeding on algae, dead plant material, detritus and uneaten fish food. They usually do not bother live plants, but they are known to reproduce rapidly when an ample food supply is present.
Pond snails can be kept with peaceful community fish and make great scavengers in shrimp tanks. To prevent populations from getting out of control, keep organic debris to a minimum by doing regular water changes, vacuuming debris and feeding sparingly.
Water Quality Requirements
Snails are not very fussy when it comes to their water parameters, but it is important to maintain healthy conditions in their aquarium by feeding sparingly, doing regular water changes and maintaining good filtration. Test water chemistry regularly to make sure you are providing the right conditions for all your aquatic pets.
How and What To Feed Snails
Snails naturally feed on algae, dead plant matter and bits of fish food that fall to the bottom, but they can also be fed Aqueon Algae Rounds and Bottom Feeder Tablets. Snails – and shrimp – need an ample supply of calcium for healthy shell growth, so if you use reverse osmosis or deionized water, add Aqueon Water Renewal to replenish essential minerals and trace elements. You can also place a little crushed coral in your filter, add liquid calcium to the aquarium, or even feed your snails Zilla Aquatic Turtle Food to make sure they're getting enough calcium. If you are more of a "naturalist", feed your snails blanched kale, spinach, Chinese cabbage, green beans or broccoli, as these vegetables are all rich in calcium. Feed sparingly and remove uneaten food to avoid water quality problems.
Avoid Introducing Nuisance Snails to Your Aquarium
Nuisance snails have an uncanny knack for making their way into aquariums, and once they are there, it can be extremely difficult to eliminate them. To avoid this happening, take the following precautions:
- Soak décor items from other tanks in bleach water or scrub them thoroughly before placing them in your aquarium.
- Inspect used gravel thoroughly before placing it in your tank. If you are unsure of its origin or there are nuisance snails in the tank it came from, do not put it in your aquarium!
- Soak live plants in a solution of 2 to 3 tablespoons of Alum powder per gallon of water or quarantine them for at least 15 days in a separate aquarium before introducing them to your display tank.
Getting Rid Of Nusiance Snails
You cannot always eliminate nuisance snails completely, but you can drastically reduce their numbers by doing the following:
- Vacuum gravel regularly and siphon out dead plant material and detritus to eliminate their food supply.
- Feed your fish less to control the amount of food and waste available to snails.
- Physically remove snails by picking them out by hand, using a snail trap or baiting them. Place Aqueon Algae Rounds, Bottom Feeder Tablets or lettuce leaves in the aquarium, leave them overnight and remove them with the attached snails in the morning! Red Ramshorn snails can be netted from the surface when they come up to breathe.
- Crush a few snails at a time and let your fish eat them!
- Introduce Assassin snails to eat your nuisance snails.
- Certain species of fish, including loaches, catfish, cichlids and puffers eat snails, and they can be an effective way of lowering nuisance snail populations. Always research fish before purchasing them to make sure they are suitable for your tank size and compatible with its residents.
- Use snail-killing products. While chemicals should always be your last resort and should be used with extreme caution, they can and do work. The problem with chemical treatments is that some are harmful, if not lethal, to plants, shrimp, other invertebrates and certain sensitive fish, so they will have to be removed if you choose this method. In addition, a mass die-off of snails can over-burden your filter and cause ammonia and nitrite levels to rise.
Can I use Medications And Other Additives with Snails?
Some medications contain copper sulfate and other chemicals that are harmful to snails and other invertebrates. Most other water treatments are safe to use in the presence of aquarium snails. Always read package instructions and ingredient lists before using any treatment in your aquarium.
Snails are part of nature, and as such, they can be a valuable and interesting addition to an aquarium.