Fishmatrix is the world's largest online collection of scientific fish illustrations. The database contains more than 940 illustrations of North American fishes, drawn from actual specimens by Joseph R. Tomelleri. The database is the result of 25 years of ongoing work by the artist.

State and Federal agencies, Universities, private companies, museums, and not-for-profit corporations can subscribe to the database and receive a license for a custom browser specifically tailored to their local fauna.

Fish images are categorized and searchable by common name, scientific name, and family name, and can also be designed to search by any geographic unit, including state, specific lakes, streams, watershed, forest, saltwater/freshwater, etc. Distribution maps, regulations, species status, etc., can also be added to the database by the purchaser.