Sea anemones are the epitome of sit-and-wait predators, which minimizes putting energy into searching for food. The general anemone relies on water motion or prey locomotion until food is within reach of its capture surfaces. Pre-feeding responses such as expansion of the oral disc, opening of the mouth and protrusion of the actinopharynx¹, and extension and twitching of tentacles may be stimulated by water soluble components of prey. The anemone then waits for sessile prey dislodged by foraging predators or wave action to fall onto their tentacles or oral disc, or simply grabs onto motile prey that swim into its tentacles. Tentacles are equipped with cnidae (see Defense Mechanisms) that assist in prey capture by wounding and immobilizing the prey¹. It may also feed on planktonic prey that is moved to its tentacle tips by ciliary action, which are then inserted into its mouth² (Figure 1).

A spatially separate range of mechano- and chemoreceptors differing in thresholds, specificites and effectors are noted to be involved in the complete sequence of feeding behavior, which begins with the perception of food and ends at its ingestion. Effectors such as muscles can be coordinated by electrical conduction systems. On the other hand, effectors such as pharyngeal cilia apparently do not involve any electrical conduction system during pharyngeal ciliary reversal at the actinopharynx⁴ (see Digestive System). Behavioral studies have indicated that the chemoreceptors involved in various feeding behaviors are situated on the tentacles, oral disc, peristome and actinopharynx, but this may differ with some species¹.

In the case of C. adhaesivum, it is both carnivorous and a filter feeder, and will feed on chopped fish or shrimp⁴. Its tissues also contain symbiotic zooxanthellae that can photosynthesize⁵ (see Digestive System for more detail).