To determine the quality of fossil preservation in the early Eocene Fossil Butte Member (FBM) of the Green River Formation in Fossil Basin, Wyoming, we excavated 1,133 fishes from the upper 30 cm of the 45.7-cm-thick FBM. Each fossil was evaluated for its relative skeletal articulation, ranging from near perfect articulation to almost complete disarticulation, and placed into one of four stages. About 70% of the fishes have near-perfect articulation of the skeleton. Ninety-seven percent of the specimens in the sample belong to five of 19 genera known from the FBM: †Knightia, †Diplomystus, †Cockerellites, †Mioplosus, and †Priscacara. Finally, 97% of the specimens belong to four of 15 families known to be present in the FBM: †Paraclupeidae, Clupeidae, Latidae, and Moronidae.