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 species of Aravaipa Canyon itself. Various methods are used to survey the type and abundance of fish species present at each location. The most common of these is seining, a method that involves dragging a long net through the water and catching many fish at a time. This is best done by two individuals (one on either side of the net) who run downstream, scooping up the fish that are attempting to swim upstream against the current. Another form of seining involves the same two people on either side of the net, but this time they plant the edges of the net into the