I have visited ASDM twice (2008 and 2011) and I really enjoyed seeing Life on the Rocks in its prime years. On both my visits, there was an issue finding all of the inhabitants of the exhibits, but that's part of the overall experience at ASDM.
Here are the 30 species that I noted during my 2011 visit:
Harris' Antelope Squirrel, Hog-nosed Skunk, California Leaf-nosed Bat, Elf Owl, Black-throated Sparrow, Black-tailed Gnatcatcher, Western Diamondback Rattlesnake, Tiger Rattlesnake, Speckled Rattlesnake, Black-tailed Rattlesnake, Gopher Snake, Sonoran Whipsnake, Sonoran Lyre Snake, Coachwhip Snake, Gila Monster, Desert Night Lizard, Giant Spotted Whiptail Lizard, Banded Gecko, Lowland Leopard Frog, Canyon Tree Frog, Red-spotted Toad, Bark Scorpion, Stripe-tailed Scorpion, Black Widow Spider, Western Tarantula, Giant Crab Spider, Kissing Bug, Longfin Dace, Sonora Sucker and Loach Minnow.