Mystery Snail - Complete Care Guide

The Mystery Snail (Pomacea diffusa) breathes in a way most aquarium animals don't: it has both gills and a lung, a combination that lets it survive in low-oxygen water and, more visibly, control its own buoyancy - holding air in the lung to float, releasing it to sink back to the substrate. At about 2 inches in shell diameter, it's a popular tank cleanup species available in shell colors ranging from golden yellow to jade green and deep purple.

Photo: Angel Ramos - Wikimedia Commons, CC BY-SA 4.0

Parameter	Value
Adult size	~2 in shell diameter
Lifespan	1-2 years (up to 3 with strong care)
Breathing	Gills + lung (siphon on left shoulder)
Shell colors	Yellow, blue, purple, ivory, brown, black, jade
Key care need	Regular calcium supplementation

A Dual Breathing System That Controls Buoyancy

Mystery Snail extends a distinctive elongated siphon from its left shoulder to breathe air at the surface, a behavior made possible by having a lung alongside its gills. This isn't just a low-oxygen backup system - the snail actively uses it for buoyancy, holding air in the lung to float near the surface and releasing it to descend back to the substrate, a genuinely different mechanism from the gill-only breathing most aquarium life relies on.

Calcium Isn't Optional

Shell health depends directly on calcium intake, and a deficiency doesn't just weaken the shell cosmetically - it can kill the snail. Regular calcium supplementation, alongside a varied diet, is one of the few care requirements that genuinely makes or breaks long-term Mystery Snail health, more so than for most fish sharing the same tank.

A Wide Color Range for One Species

Golden yellow, blue, magenta, purple, ivory, chestnut brown, black, and jade green shells all belong to the same species, Pomacea diffusa, with foot coloring varying independently between light and dark. That range gives keepers real visual choice without needing to identify or source a different species for each color.

One Medication Class to Avoid

Copper-based medications, sometimes used to treat fish for parasites or disease, are toxic to Mystery Snail and most other invertebrates. Treating a mixed fish-and-snail tank requires checking medication labels for copper before dosing - a lapse here is a common, avoidable cause of sudden snail deaths.

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