For an angler judging whether the fishing is worth the drive, the stocking record is the fishing report. Haiseldean Lake is a put-and-take angling fishery, stocked with catchable game fish: 10 recorded releases totalling 29,000 fish (Westslope (Yellowstone) Cutthroat Trout, Rainbow Trout), last stocked 2004-10-06.
Stocking appears to have wound down after 2004. Confirm whether it is still topped up or now fishes as a residual, wild population. The chart below shows the full release history.