Mystery Snail

Pomacea bridgesii is a South American apple snail commonly sold in gold, blue, ivory and black shell colours. Unlike some of its relatives, it is plant-safe, preferring decaying matter and algae over living leaves, which makes it a popular cleanup animal for planted tanks.

Tank & water. A mystery snail's shell can reach 5–6 cm (2 in) across, so allow a few gallons per snail — a 38 litre (10 US gallon) tank comfortably houses one or two. They do best in harder, alkaline water around pH 7.0–8.0 and temperatures of 20–28 °C (68–82 °F). Adequate calcium and general hardness are important, as soft or acidic water pits and erodes the shell.

Temperament. They are entirely peaceful and coexist with community fish, though large or nippy fish may harass them. Like all invertebrates they are sensitive to copper in medications and additives. They breathe using a siphon at the surface and lay eggs above the waterline, so a tight lid is useful both to keep humidity and to stop wanderers.

Diet & care. Mystery snails scavenge leftovers, algae and biofilm and appreciate supplemental sinking foods, algae wafers and blanched vegetables such as courgette, spinach or blanched lettuce. A well-fed snail with good water hardness grows a smooth, unbroken shell; a cracked, thin or pitted shell is a sign that calcium, general hardness or diet need attention, and adding a cuttlebone or mineral supplement helps. They are relatively short-lived, typically living about one to two years, and a snail found sealed behind its trapdoor may simply be resting rather than dead. Unlike bladder or ramshorn snails they will not overrun a tank on their own, because the sexes are separate and females lay their distinctive pink egg clutches above the waterline, which can simply be removed if young are not wanted.