Aquarium snails

Snails graze algae and turn over the substrate, from nerites and mystery snails to marine cleanup species. Each profile lists the conditions a snail needs and how it behaves in a tank.

Tank size: 5–21 gal; 5 gal (19 L) to 21 gal (80 L); half the list needs 7 gal (25 L) or more
Temperature: 72–82°F; 22–28°C, most of the list
pH: 7.0–8.2; Most of the list
Difficulty: 43 easy; 7 medium
Temperament: 49 peaceful; 1 mostly peaceful

50 species

Start here

Nerites and mystery snails

The nerite snails are the algae eaters: the zebra, tiger, olive and horned nerites stay around 1 inch (2.5 cm), list 5 gallons (20 liters), are marked beginner and clean glass and rock without touching plants. They lay white eggs that never hatch in freshwater, so the count stays where you put it. The mystery snail is the pet snail, 2 inches (5 cm), marked easy, plant safe and fond of blanched vegetables. The red ramshorn and the Malaysian trumpet snail breed on their own and do the tidying: the ramshorn on leaves and glass, the trumpet snail in the substrate, where it turns the sand at night.

The rule

What a snail needs from the water

A shell is calcium carbonate, and soft, acidic water dissolves it. Snails want a pH above 7 and hard water, or a cuttlebone in the tank and calcium in the food. They also need feeding: a nerite starves once the glass is clean, so algae wafers and blanched vegetables go in when the algae runs out. Copper kills snails at any dose, which rules out most fish medications and some fertilizers. And nerites climb, so an open-topped tank loses them over the rim.

01
Calcium and pH above 7
Soft, acid water pits the shell
02
Feed them
Wafers and blanched veg once the glass is clean
03
No copper
Medications and some fertilizers kill snails
04
A lid for nerites
They climb out of an open tank

Breeders and hunters

Pest snails, and the snail that eats them

The bladder snail, the ramshorns and the Malaysian trumpet snail arrive on plants and multiply to match the food supply, which makes them a sign of overfeeding rather than a problem in themselves. The assassin snail is the fix: 1 inch (2.5 cm), marked easy, and it hunts other snails and leaves plants alone. Two snails to keep out of a planted tank: the apple snail reaches 5.9 inches (15 cm), lists 21 gallons (80 liters) and eats plants down to the stem, and the giant Colombian ramshorn does the same at 2 inches (5 cm).

Warm water

Rabbit snails and the Sulawesi crowd

The rabbit snails come from the lakes of Sulawesi and want warm, hard water: the gold rabbit snail is 2.8 inches (7 cm) for 16 gallons (60 liters) at 75–82°F (24–28°C) and a pH from 7 to 8.5, the yellow giant rabbit snail 4.7 inches (12 cm) for 20 gallons (75 liters) at 79–86°F (26–30°C). They are marked medium, they give birth to one live baby at a time, and they graze on soft algae and leftovers without touching most plants. The Himalayan rabbit snail is the easy one at 2 inches (5 cm). The blue turbo snail is another Sulawesi native for 79–86°F (26–30°C), and the black devil snail is the tall, dark one at 3.9 inches (10 cm), marked easy.

Saltwater

The reef clean-up snails

A reef crew is a mix, because each snail cleans a different surface. The trochus snail grazes glass and rock at 1.2 inches (3 cm), rights itself when it falls and breeds in the tank. The astraea snail does the same job but cannot turn itself over, so it needs a hand up. The cerith snail works the sand and the glass at 1.6 inches (4 cm). The nassarius snail lives in the sand and eats leftover food, not algae. The Mexican turbo snail is the big grazer at 2.4 inches (6 cm) and knocks over loose frags. The fighting conch plows the sand bed at 3.1 inches (8 cm) in 20 gallons (75 liters). All of them are marked beginner or easy.

By the numbers

Smallest

Largest

Most peaceful

FAQ

Common questions

Do snails clean the tank?

They eat algae, leftover food and dead leaves, which keeps the glass and the sand tidy. They do not remove waste; they add to it, so the water changes stay the same.

Will nerite snails breed in my tank?

They lay small white eggs on the glass and the rock, but the larvae need brackish water, so the eggs never hatch in a freshwater tank. The eggs stay until you scrape them off.

How do I get rid of pest snails?

Feed less, since the population tracks the food. Add assassin snails, which hunt bladder snails and ramshorns. Skip the chemical treatments, which contain copper and kill shrimp and the snails you want.

Why is my snail's shell pitted or white?

The water is too soft or too acidic and the shell is dissolving. Raise the hardness, keep the pH above 7 and add a cuttlebone or calcium-rich food.

Are snails safe with plants?

Nerites, mystery snails, ramshorns, trumpet snails and rabbit snails leave healthy plants alone. The apple snail and the giant Colombian ramshorn eat plants and belong in a tank without them.

How many clean-up snails does a reef need?

A few of each kind rather than a crowd of one. Start with trochus and cerith snails for the rock and glass, add nassarius snails for the sand, and add more only when the algae outpaces them.

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