"Theodoxus fluviatilis dalmaticus" in Lake Ohrid can reach population densities up to 6412 snails per m².The species was found in population densities of up to 9000 snails per m² in a spring of the Anços river in Central Portugal, where there is a stable temperature of 15.3–16.6 °C, which allows continuous reproduction in "Theodoxus fluviatilis".