Freshwater Limpet Snail (Theodoxus fluviatilis)

Theodoxus fluviatilis, the Freshwater Nerite or River Limpet, is a small native European freshwater snail found on rocks and submerged surfaces in clean, well-oxygenated rivers, streams, and lakes across Europe, including Belgium and the Netherlands. Its low-profile, rounded shell bears a charming variety of dark patterns — zigzag, striped, or marbled — on a cream, olive, or brownish background, with considerable individual variation. In the aquarium it excels as an algae and diatom grazer, methodically working across rocks, glass, and plant leaves. Its natural preference for cooler, hard water makes it particularly well suited to cold-water and temperate European biotope aquariums housing species such as European minnows, loach, or gudgeon, though it can adapt to warmer setups within its tolerance range.

Provide hard, well-oxygenated water with moderate flow, reflecting its natural river environment. Best at cooler temperatures below 22°C — keep below 25°C for long-term health. Provide calcium-rich water (GH 8–20) to support shell development. Feed on algae and diatom growth on rocks and glass; supplement with algae wafers if natural growth is limited. Completely safe with all plants and peaceful fish. Does not reproduce rapidly in captivity.