Mystery Snail

Overview

• The mystery snail is a golf-ball-sized apple snail bred in gold, blue, ivory, purple, and magenta, and it is far more animal than most people expect from a snail.
• It cruises the glass on a broad foot, sweeps the water with long swaying tentacles, and extends a snorkel-like siphon to the surface to breathe air.
• Most animals sold under the old name Pomacea bridgesii are now classed as Pomacea diffusa, but the care is identical.

• It is a genuine beginner invertebrate, with two caveats that catch new keepers.
• It must actually be fed, because unlike a nerite it cannot live on tank algae alone.
• It also needs hard, calcium-rich, copper-free water, or its shell slowly dissolves.

• Unlike pest bladder and ramshorn snails, mystery snails have separate sexes and lay their eggs above the waterline, so a single snail can never overrun a tank.
• Unlike its invasive relative the channeled apple snail, a fed mystery snail leaves healthy plants alone.

Housing

• Allow at least 19 litres (5 gallons) of cycled, mature water per snail, so one snail suits a 19-litre tank and a pair belongs in 38 litres (10 gallons) or more.
• These snails carry a surprisingly heavy bioload for their size, so err larger and run real filtration rather than crowding them.
• A tight-fitting lid is not optional, because they climb above the waterline and a snail that escapes overnight dries out and dies.
• Leave a 2-5cm air gap under the lid, since they surface to breathe and females lay eggs in that gap.

• Keep the water at 20-26C (68-78F), with the cooler end of that range noticeably lengthening lifespan by slowing the metabolism.
• Aim for pH 7.0-8.0 and moderately hard water of GH 8 or above (roughly 150ppm and up), and keep some carbonate hardness (KH) to hold the pH steady, because soft acidic water permanently etches and pits the shell.
• They are as sensitive to ammonia and nitrite as any fish, so never add one to an uncycled tank.

• Any copper in the water is lethal, so check medications and some plant fertilisers before dosing.
• Expect them to occasionally let go of the glass and free-fall to the substrate, which looks alarming and is completely normal.

Diet

• This is a scavenging omnivore, not a self-sufficient algae eater, and slow starvation of snails expected to clean the tank is the most common way keepers get it wrong.
• Feed sinking algae wafers, invertebrate pellets, and blanched vegetables such as zucchini, spinach, and green beans several times a week.
• It will also tidy up biofilm, soft film algae, and any fish food that reaches the bottom.

• Calcium is a dietary requirement, because the shell is built from it.
• Offer cuttlebone, calcium-enriched snail foods, or homemade calcium-rich snail jello alongside hard water.
• Smooth, solid new growth at the shell lip shows the diet and water are right.

• Remove uncooked vegetable leftovers within 24 hours before they foul the water.
• A well-fed mystery snail ignores live plants, while a hungry one may start rasping the softest leaves.

Health

• The shell is the health report.
• Pits, erosion, and thin white patches mean the water is too soft or the diet lacks calcium, and existing damage never repairs, it can only be stopped.
• A healthy snail also pulls fully into its shell and seals the operculum, its trapdoor, snugly shut.
• A snail hanging limply out of its shell and unresponsive to touch is in serious trouble.

• Copper is the great snail killer, so read the label of every medication before treating a tank that houses one.
• Floating at the surface is usually just trapped air in the lung and resolves on its own.
• Before discarding a motionless snail, smell it, because a dead snail smells unmistakably foul within hours while a dormant one, which can stay closed for a day or two, smells of nothing.

• Be honest about the timescale, since 1-2 years is a full life for this species, warm tropical tanks push it toward the short end, and only a cool tank tends to reach three.
• Females lay pink egg clutches above the waterline, and unwanted clutches should be removed and frozen within a day or two, before 50-200 hatchlings arrive.
• Never release snails or eggs into local waterways, because apple snails are serious invasives and release is illegal.

Temperament

• Completely peaceful and unexpectedly engaging, a mystery snail patrols every surface of the tank, snorkels at the waterline, and drops off the glass to parachute down to food.
• Many keepers find theirs learns feeding time and heads for the usual spot.

• It suits calm community fish such as tetras, rasboras, corydoras, and livebearers.
• Avoid tankmates that pick at its tentacles or eat snails outright, including tiger barbs, some bettas, loaches, puffers, assassin snails, and large cichlids.
• A constantly harassed snail stays sealed in its shell and quietly starves.

• It is equally content alone or in a group, provided each snail has its 19 litres (5 gallons) of water.
• Keep in mind that any mixed-sex group will produce egg clutches, and a lone female can lay fertile eggs for months from stored sperm.

Is your enclosure big enough?

Check your own enclosure against this

Is this urgent?

In a fish tank the patient is usually the water. Test before you treat — dosing a healthy tank for a disease it does not have makes things worse.

Go now

Today

Soon

Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.

This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.

What it really costs

Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.

Work out the cost of a mystery snail