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
Fish stringer Fish stringer A fish stringer is a line of rope or chain along which a fisherman can string fish so they can be immersed and kept alive in water. A rope stringer "(pictured)" is the simplest type of fish stringer. It consists of a line of rope or wire with a stringing needle made of metal or hardwood at one end. The other end usually has a removable wire ring which can be used to secure the stringer. Using the needle, the stringer is threaded through the fish gill and out through its mouth, or better, it is threaded through