About 60 species of the genera Aldrovanda and Utricularia are submersed aquatic or amphibious carnivorous plants. They all are strictly rootless and take up mineral nutrients for their growth from the ambient water and captured prey through their trap-bearing shoots. These species represent a specific ecophysiological group that are dissimilar in their principal morphological and physiological features from terrestrial carnivorous plants and from rooted and nonrooted aquatic noncarnivorous plants. I review the ecology of habitats of aquatic carnivorous plants; characteristics of their growth traits, photosynthesis, and mineral nutrition; regulation of the investment in carnivory in Utricularia; biophysical and physiological peculiarities of Utricularia traps; and turion ecophysiology. Open questions of the ecophysiology of aquatic carnivorous plants are discussed.