I found this UC Davis fish application. It allows you to search specific fresh waters in Calif. and it will tell you what fish you can encounter there. It also has a pretty good description of each species. If you have any input on the website, it's in the beta version, and they are looking for input to make it better....try it out...it's pretty fun and good reading..
http://calfish.ucdavis.edu/CalFishApp/
Any feedback on the UCD app?