Mystery snails: Can they live with goldfish?

Mystery snails (Pomacea bridgesii) are a type of snail that is commonly kept in aquariums due to their ability to clean the algae off the tank walls, which can help with the overall health of the fish. They are very popular due to their cleaning and waste management skills. Mystery Snails are a good snail for beginners because they are easy to care for and adaptable. They enjoy community tanks and can be kept with most goldfish, particularly the ones that are slow moving and require the water to be kept cleaner. Faster more aggressive goldfish might become curious and eat the snails if they are small enough or cause damage to the shell. It is recommended that one snail can live in a five-gallon tank, otherwise, the tank can become too crowded. The snails come in a broad range of colors and can grow to a max size of two inches, most of them reaching 1 ½ inches in size. They are a peaceful type of species and are safe to keep with other companions in the tank such as various fish and other snails. They can be sensitive to copper in the water so verifying what you are feeding your fish and that it doesn’t contaminate the water for the snails is important. The snails will eat fish food as well as the algae off the tank walls and keeping them adequately fed will prevent them from eating live plants in the aquarium. These snails are herbivores and can live up to one year.

When you go to buy a snail from a store, watch the snails in the tank for some time. Make sure that they are moving around well and hanging onto the wall. You do not want to purchase a snail that has any damage to the shell or is not moving around. This can signify a health issue with the snail. Make sure you purchase a snail from a reputable place if you aren’t purchasing them in person.

Mystery snails come in a variety of colors. Some common colors that are seen are blue, black, gold, and purple. The most popular colors tend to be black or brown, gold and ivory. The shells of these snails can be a solid color, banded, or a gradient. Their foot stalk and head are white most of the time and this gives them a pop of color when they are out of their shell. Due to the various ways the shell can color and the different colors they can be, there ends up being an endless amount of color combinations.

Their shell has the apex (top) of the spiral more to the side than the top of their aperture (opening). As adults they tend to have four small whorls (spirals) on their shells. They have an operculum that is used to close the opening of the shell and this helps protect them from predators. The operculum can also show the health status of the snail. If it isn’t sitting right on the snail then something is wrong and once the snail dies the operculum will fall off. They have two large tentacles that are used to sense the environment and find food. Located directly behind these are the eyes which are used to detect motion and light. The eyes are placed on cephalic eyestalks and if these are severed, they can regrow since there are no other sensory organs in the eyestalk. The mouth is below and a second pair of tentacles that are used for feeding. They also have a siphon which is used to pass water through the gills and is located on the left side of the head.

Mystery snails will spend most of the time grazing on algae around the tank or on the tank walls. They are very active and eat a lot of algae in the tank. They will hide in their shell if they are bothered by fish in the aquarium and after some time will come back out and continue eating. If an aggressive fish bothers them too much, then they will spend more time hiding and less time eating which means they will not be cleaning as much of the algae off as they could, and this consistent stress is unhealthy for the snail. They have a quirky behavior where they will go to the top of the aquarium and intentionally quickly slide down the glass to the bottom. They also be at the top of the water line and will extend a tube out of them that will go above the water and move it back and forth to breathe.

In the wild, these species of snails are found in Paraguay, Brazil, and Bolivia. The Chinese species is starting to become a problem in the Northern part of North America and certain species found in Japan and China are considered invasive in some areas. They natively live in ponds, swamps, and rivers feeding on dead or decomposing plants. They won’t feed on anything live unless they don’t have another option. They are also wary of any other animal that can cause damage to their shell such as large fish and birds. There are similar snails that are from the family Viviparidae that were brought to California for food trade because they get to a much larger size.

Mystery snails eat dead and rotting plants in the tank so having living plants will provide a consistent small food source. They enjoy the algae buildup that is found on the substrate such as rocks or sand and they will eat the algae that accumulates on the glass. They are considered optimistic scavengers so they will eat whatever sounds good to them and is available. Keeping a high to medium level amount of vegetation will allow them enough to snack on as leaves die and drop off. You will be able to see where they have traveled in the tank by their “tire tread” pattern they leave on the tank as they move around. If watching them, it won’t seem like they move much but over time you will see the tread grow. They use their radula to scrape the algae off the glass.

Providing supplements will keep them healthy and cleaning the tank. Their shells are rich in calcium, so they need to be provided with a supplement to keep their shell strong. There are many kinds of supplements out there to choose from. Leafy greens that are softly blanched, such as zucchini or lettuce, are a good treat for them.

In a tank enclosure, there are a few good live plants that can be added, Java Fern, Java Moss, and Hornwort are common ones placed in a tank. If food is not readily available, then the snails will leave the tank so keeping a tight -fitting lid on their enclosure is recommended.  They do not require a specific substrate on the tank floor so gravel, sand, or pebbles are fine as long as the tank companions will enjoy the substrate placed. Snails are extremely sensitive to copper in the water, so it is imperative that the food fed to the tank does not have copper or a water conditioner that removes copper is used. Adding calcium is also recommended due to the high levels of calcium needed to maintain the shell health. Calcium can be either fed in a powder form or feeding calcium rich foods such as spinach.

Snails do best with a Ph level of 7.6-8.4 and water temperature of 68F-84F. They don’t like rapid changes in the water and do best with moderately moving, highly oxygenated waters. Goldfish enjoy similar waters and don’t enjoy rapid changes in water either which makes snails and goldfish good tank companions.

Tank companions are a welcome addition to an aquarium with snails. Snails enjoy peaceful fish company such as tetras, guppies, and killfish. Some other companions that are not fish are other snail species. Ramshorn Snails, Ivory Snails, and Netrite Snails are good companions that are also snails. Certain fish such as Oscars, cichlids, and crayfish will eat snails if they are in the same tank. Goldfish will eat small snails if they are not fed enough and will tend to nibble on snails to check if they can fit in their mouth. Feeding goldfish regularly will prevent them from trying to eat the snails in the tank. It is possible to house to many companions in the same tank. This can cause issues with improper nutrition, damaged shells, or growth defects. It is recommended to have one snail per five gallons of tank.

Snails can carry some parasites so it’s important to make sure that you have parasite free snails in the tank. Two common ones are Rat lungworm and Grub worms. Rat lungworm larvae use snails as a temporary host and are seen mostly in wild snails. Grub worms are small white cysts on a snail’s foot. When they rupture, the flukes are released into the water where they can infect the fish in the tank. They will encyst the flesh of fish and will have to be removed manually. The worms will stay with the host until they die. The worms, however, can’t reproduce in the tank. Grub worms are usually seen in aquariums where wild caught snails are housed.

Most problems with snails are shell related and if damage is caused then, depending on the severity of the damage, the shells can be patched with fish safe epoxy, but it is very risky. It is important that once you obtain a snail that you quarantine it in its own tank for 28 days. A common way to quarantine a snail is to put it in a jar with a piece of a live plant to keep the water oxygenated and food for the snail.

It is possible to breed snails in an aquarium and it is pretty easy. Snails are gonochoristic which means that there needs to be a male and female snail for reproduction to occur. They will mate without help or tank condition altering. The female will lay the eggs above or at water surface in a cocoon. The cocoon looks like a large frothy clump and holds on average of 100 eggs that are pinkish in color. The eggs will hatch within a month. The babies once hatched will fall to the tank floor and start eating. Making sure there is enough food is imperative and sufficient space above the water level for the cocoon and the newly hatched eggs. If you are housing goldfish in the same tank as the breeding snails, then you will need to remove the cocoon of snail eggs because goldfish have a tendency to eat the eggs of snails.

When all is said and done, snails and goldfish are easy to house together as long as you have slow moving peaceful goldfish. Snails are great at keeping the tank clean and healthy for the fish. They don’t bother the goldfish and enjoy the same type of water as goldfish. They are able to eat the same food and enjoy the same treats, just make sure that copper isn’t in the food you feed. Snails also add a lovely pop of color to the tank. Making sure you obtain healthy parasite free snails and properly quarantining them will allow a year or so of easier tank maintenance and a vibrant community tank. These two species will coexist happily in the same tank.