Species description

Care, breeding and tankmates

Invertebrate profile

Diet

Biofilm grazer

The primary diet of Theodoxus fluviatilis consists of various types of algae, biofilm, and decaying plant matter found on aquarium surfaces. It is an excellent clean-up crew member but may require supplemental feeding. Sinking algae wafers and blanched vegetables should be provided if natural food sources are depleted.

Ecological role

Scavenger

In its natural habitat, Theodoxus fluviatilis plays a crucial role as a detritivore and primary consumer, helping to process organic waste. By constantly grazing on algae and detritus, it prevents excessive nutrient buildup and keeps surfaces clean. This ecological function translates perfectly into the closed ecosystem of a home aquarium.

Shock sensitivity

High

Theodoxus fluviatilis is remarkably sensitive to sudden fluctuations in water parameters, particularly temperature, pH, and hardness. Rapid changes can induce osmotic shock, leading to lethargy, shell damage, or death. A slow drip acclimation process over several hours is highly recommended when introducing it to a new tank.

Calcium and minerals

High

Adequate calcium levels are absolutely critical for Theodoxus fluviatilis to develop and maintain a strong, healthy shell. Soft, acidic water will gradually erode the shell, exposing the snail to infection and premature death. Hobbyists should supplement the water column or diet with cuttlebone, coral skeleton, or specialized mineral blocks.

Molting

Shell growth

Unlike crustaceans, Theodoxus fluviatilis is a gastropod and does not undergo a molting process to grow. Instead, it continuously adds new calcified layers to the aperture of its existing shell as it matures. Therefore, observing continuous, healthy shell growth lines without pitting or cracks is the best indicator of its well-being.

Reproduction

Oviparous

The reproductive strategy of Theodoxus fluviatilis varies, but many require specific conditions such as brackish water to successfully yield viable offspring. While they may lay eggs frequently in a freshwater aquarium, the larvae often fail to develop without the proper salinity. This trait makes them ideal for aquarists who wish to avoid overpopulation issues.

Compatibility & tankmates

Peaceful

Theodoxus fluviatilis is entirely peaceful and possesses no means to harm other tank inhabitants, making it perfect for community setups. It should not, however, be kept with aggressive loaches, pufferfish, or large crayfish that will prey on it. Ideal tank mates include small tetras, rasboras, and dwarf shrimp.