Fish intelligence in paradise fish ("Macropodus opercularis") which avoid places where they have experienced a single attack by a predator and continue to avoid for many months. A number of studies have shown that fish can retain information for months or years. Anecdotally, channel catfish ("Ictalurus punctatus") can remember the human voice call announcing food five years after last hearing that call. Goldfish remember the colour of a tube dispensing food one year after the last tube presentation. Sockeye salmon still react to a light signal that precedes food arrival up to eight months since the last reinforcement. Some common rudd and
Wooden fish can differ amongst wooden fish depending on the size, type of wood used, and how hollow the wooden fish is. The instrument is carved with fish scales on its top, and a carving of two fish heads embracing a pearl on the handle (to symbolize unity), hence the instrument is called a wooden fish for that reason. In Buddhism the fish, which never sleeps, symbolizes wakefulness. Therefore, it is to remind the chanting monks to concentrate on their sutra. Often the mallet used to strike the fish has a rubber coated tip to provide a muffled, but clear sound when