Kokanee salmon lake acidity. As a result, the kokanee was believed to have gone extinct in the 1940s. In 2011 a few fish were found in an isolated lake on Mount Fuji. The Japanese kokanee varies from its sea-going sockeye relative in a few ways. The black kokanee breeds in March at a depth of 30–40 feet, while sockeye salmon breed in the fall and have a different number of gill rakers than the kokanee. In addition, the black kokanee is much darker in color than the sockeye or any other kokanee population. The fish has been introduced to different lakes around
Paradise fish less aggressive than the wild type, but also less hardy, having more trouble with low temperatures. Paradise fish The paradise fish, "'paradise-fish"', paradisefish, or paradise gourami ("Macropodus opercularis") is a species of gourami found in most types of fresh water in East Asia, ranging from the Korean Peninsula to northern Vietnam. This species can reach a standard length of , though most are only about . Paradise gouramis were one of the first ornamental fish available to western aquarium keepers, having been imported 1869 to France by the French aquarium fish importer Pierre Carbonnier in Paris. The paradise fish is