Subject matters of experiments and observations of water animals in school aquarium III - food behaviour of water animals
Abstract
Food intake belongs to fundamental manifestation of animals. In aquaria can be presented various types of food specialization.
Filter-feeding activity can be presented in bivalve mollusks (e.g. zebra mussel Dreissentia polymorpha) removes phytoplankton and other suspended matter from the water column, both through ingestion and sedimentation of particles. Scrapers, which are often also referred to as grazers, include also e.g. snails and many types of immature aquatic insects.
Scrapers feed on substrata surfaces, consuming attached algae, heterotrophic components of biofilms, and associated deposited organic sediments. Scrapers like the apple snail (Pomacea), algae eater (Gyrinocheilus), bristlenose catfish (Ancistrus) can be demonstrated in school aquaria.
Predators like dragonflies have long mouthparts that extend. They are examples of predators that hunt mostly by sight.
Some other predators hunt by scent. Animal ambush predators usually remain motionless (sometimes hidden) and wait for prey to come within ambush distance before pouncing (see e.g. water stick insect Ranatra linearis, water scorpion Nepa cinerea).
Extra-oral digestion can be demonstrated by larvae and adults of the great diving beetle (Dytiscus marginalis).