How Many Snails Per Gallon?

Experienced aquarists can offer valuable insights based on real-life experience regarding the number of snails per gallon. While it’s true that you learn more about snails as you keep them, it’s important to familiarize yourself with the appropriate snail-to-gallon ratio before starting your snail-keeping journey. So, how many snails per gallon?

For mystery snails, maintain a ratio of 1 snail per 5 gallons (19 liters) of water. In a 5-gallon aquarium, one nerite or rabbit snail is sufficient, while cerith snails can be kept in groups of 3. For saltwater tanks, the general guideline is to have one snail per gallon and scale up accordingly.

This article explores the requirements necessary to ensure the comfort of different snails per gallon, considering that the number of snails can vary based on their size and species.

Snail Species Per Size

A tabular representation is provided below, indicating the growth size of various snail species when they reach adulthood.

Next, let’s examine the typical gallon capacities and the corresponding recommended number of snails. This information is presented in the following tabular format:

Freshwater Snail Aquarium Capacity for 3-Inch-Sized Snails  

The numbers presented in these tables might imply that a 5-gallon tank should accommodate 2 snails. However, it is important to consider additional factors such as other occupants like fish, plants, sand, stones, wood, or filters occupying space within the aquarium.

This information gives novice aquarists a basic understanding when determining the appropriate number of snails for their aquarium.

In cases where snails reproduce rapidly, like mystery snails, or tend to generate excessive waste, such as rabbit snails, it is often advisable to have fewer snails in relation to the tank’s volume, especially when more gallons are available.

The Ecological Mysteries of the Chinese Mystery Snails

The Chinese Mystery snail, originally from Asia, was introduced in the United States in the 1890s after being imported for food by Asian communities in California and San Francisco.

Even though it is native to the Asian continent, the snail found its way to the United States at the beginning of the 1890s. Asians living in the United States, specifically in California and San Francisco, imported mystery snails for food until they decided to keep them in aquariums.

Later, the Mystery Snails lived in aquariums solely for aesthetic purposes and also commonly reared in landscaping ponds.

Chinese mystery snails can exist in large numbers in tiny environments. However, the dense population harms their well-being, which scientists consider severe.

Behaviorally, mystery snails can co-exist with each other, but they tend to intimidate other species. Mystery snails in the captivity of aquariums need special consideration for longer-term housing.

A 5-gallon (19-liter) tank can hold up to 2 mystery snails, but a double-sized tank is recommended for long-term healthy living.

Most aquariums can be made of glass or plastic, which does not affect the snails’ health. However, the tanks should have a fixed cover that also allows for sufficient aeration while keeping snails from leaving the tank unnoticed.

Mystery snails also need enough space above the water. It is recommended that a 2-to-4-inch (5-10 cm) air space be maintained between the aquarium cover and the water. This space provides enough air circulation and allows the snails to breed without hindrances.

Apart from these small, specialized provisions, mystery snails are not too much trouble to keep. At most, they will live for one year.

Within the year, they will focus on staying alive and keeping the tank clean, provided fresh water and food are regularly provided. At the end of the one year, most mystery snails will die naturally, and you can replace them with a new batch in adherence to the number of snails per gallon.

Most importantly, mystery snails prefer resting in darker areas of the tank. Water plants or artificial rocks can provide dark spaces in an aquarium.

The Housing Needs of the Rare Rabbit Snail

Rabbit snails are highly favored by many aquarists, not only for their ability to clean aquariums but also for their appearance and remarkable social capabilities.

These snails can reach sizes of up to 5 inches (13 cm) when they reach adulthood, and their size dictates their needs within a captive aquarium setting. 

In contrast to mystery snails, which arrived in the United States before the 19th century, rabbit snails became available in 2008. They originate from Indonesia, specifically from Lake Poso and Malili Lakes.

Despite their popularity among enthusiasts, rabbit Snails are relatively rare and not as readily available in pet shops as other snail species. However, they can be found in freshwater lakes and slow-moving waters in warm climates.

Like other snails, rabbit snails thrive in spacious environments. If you enjoy more extreme tank setups, keeping a single snail in a 25-gallon (96 liters) tank is acceptable.

However, the general guideline suggests five snails can flourish in a 30-gallon tank (114 liters). Nonetheless, I would still recommend opting for larger tank sizes when housing several snails to achieve optimal results.

Cerith Snails in a Saltwater Reef Tank

Cerith snails thrive in saltwater environments. Therefore, they prefer a reef tank that mimics a seabed, complete with mature sand and mud.

Adult cerith snails attain a maximum diameter of 1.5 inches (6 cm). One adult snail is considered enough for a 5-gallon (19-liter) reef tank based on size.

In extreme cases, two snails can fit a 5-gallon tank. Some adult snails sometimes reach maturity at a maximum of 1 inch (2.5 cm). The tiny sizes of the cerith snail reduce the risk of bio-overload in an aquarium, especially given that they prefer to stay amongst live rocks and other hidden parts of the tank.

Unlike rabbit snails, which are loved for their aesthetic additions to an aquarium, the cerith snail’s voracious nature is unmatched. Marine aquarists love the tiny cerith snails because they are unobtrusive.

Despite their small sizes, cerith snails also keep tanks clean and healthy, thanks to their love for algae. Their voracious nature also makes them preferable, given that they tend to eat any leftover foods from fish and other reef tank aquariums.

Summary

The number of snails that can thrive in freshwater or saltwater aquariums depends on the size and species of the snails. Different gallon requirements exist for mystery snails, rabbit snails, apple snails, turbo snails, and cerith snails.

Cerith snails are small, reaching a maximum size of one inch (2.5 cm), allowing for more snails per gallon. It is recommended to keep at least 2 or more cerith snails in a 5-gallon (19-liter) reef tank.

In contrast, only two mystery snails can comfortably live in a 5-gallon tank, while one rabbit snail is sufficient for a 6-gallon tank (23-liter).

Sources

• Cary Institute of Ecosystem Studies: The Mystery of the Chinese Mystery Snail: Ecological Impacts of an Invader
• VWR: Freshwater Snails
• Algae Barn: Aquarium Cleaning Machines: Cerith Snails in the Reef Tank