Texas Parks and Wildlife has a list of Freshwater Fishes Found in Texas.
For mammals, visit Texas Parks and Wildlife’s Texas Wildlife Identification Guide, Texas Tech University’s The Mammals of Texas, Online Edition (as they say on the page “click here to begin“), Wikipedia’s List of Mammals of Texas, and iNaturalist’s Mammals of Texas.
For birds, visit Texas Parks and Wildlife’s Texas Birds, Texas A&M University’s (Kingsville) “A Guide to Bird-watching and South Texas Wintering Birds, the Houston Audubon Society’s Common Birds of Houston, Texas, and Bird Friendly Houston’s Top Birds of Houston.
See also CCERP’s Tracking & Birding page.
You can see lots of local fauna on iNaturalist by searching locally. You could also peruse Michael’s INat account at michaelgold. The Crimson Aggie has some videos of Bobcat, Coyote, Beaver, Otter, and more along Cypress Creek.
Texas Parks and Wildlife, in Venomous Snake Safety, has some pictures and info about local venomous snakes, and on iNaturalist is a Common Snakes Identification Guide for the Houston Area. Texas Parks and Wildlife also has Wildlife Fact Sheets (good information, but does not always have pictures) for many animals, including Reptiles. Texas A&M has a pamphlet entitled Identifying Venomous and Nonvenomous Snakes in Texas, written by Dr. Maureen Frank.
If you’d like help with an injured wild animal or want someone to ID or relocate a snake, see our Rescue page for people and resources.