 Teleosts are found world @-@ wide and in most aquatic environments , including warm and cold seas , flowing and still freshwater , even , in the case of the desert pupfish , isolated and sometimes hot and saline bodies of water in deserts . Teleost diversity becomes low at extremely high latitudes ; at Franz Josef Land , up to 82 ° N , ice cover and water temperatures below 0 ° C ( 32 ° F ) for a large part of the year limit the number of species ; 75 percent of the species found there are endemic to the Arctic . 
