What kinds of foods do most aquatic true bugs eat?

Most aquatic true bugs (order Heteroptera) are predatory, feeding on a variety of small aquatic animals such as insects, crustaceans, fish, and tadpoles.12

The specific dietary habits of these insects include:

• Predatory Species: The majority of aquatic families, including backswimmers, water scorpions, giant water bugs, and creeping water bugs, are predators that hunt small aquatic organisms. Creeping water bugs, for instance, primarily prey on mollusks and insects.12
• Semiaquatic Species: Those that live on the water's surface, such as water striders and marsh treaders, are also predatory, feeding on tiny animals, plankton, or injured and freshly killed insects. Oceanic water striders are known to feed on plankton and floating jellyfish.12
• Exceptions: The water boatmen (family Corixidae) are a notable exception; they are primarily phytophagous, feeding on algae and diatoms, though they may occasionally consume insect larvae.12

In capturing their prey, these insects often use specialized front legs to grasp their victims and inject a paralyzing salivary secretion.312