No Horsethief Creek-specific exception appears in the checked Region 4 extraction, so the regional defaults apply: streams closed Apr 1 to Jun 14, trout and char catch-and-release from Nov 1 to Mar 31, and a single barbless hook requirement on all streams. Confirm the current synopsis and any in-season notices before fishing.

Horsethief Creek's confluence sits at 50.53924, -116.38649, part of the Columbia River system in the Radium-Invermere-Fairmont corridor. It runs stream order 6 (at the top of the network on a scale that runs from 1 for a headwater trickle up to 6 or more for a full river), across 331 mapped channel segments. The channel geometry reads wider and gentler than the small tributaries that feed it: median width around 32.1 m (wide), median gradient around 0.94% (gentle), and peak mean-annual discharge around 15.4 m³/s (moderate to high flow). That combination points to a valley creek with real size and volume lower down, closer to a small river than the narrow, steep feeder creeks in its own family, though no float report or boat launch has been confirmed for it.

The confirmed fish signal here is the most varied in the local Horsethief family: kokanee, bull trout, mountain whitefish, longnose dace, longnose sucker and westslope cutthroat trout across 8 records. Bull trout and cutthroat are the species worth planning around; the kokanee record most likely marks a lower-creek food pulse tied to the creek's connection with the Columbia rather than a resident population running the full length of the creek. Typical food through the system is caddisflies, mayflies, stoneflies and terrestrials, with baitfish and fry and forage fish in play wherever bull trout or kokanee are present.

Small-stream attractors and naturals are the sensible starting point: a Stimulator, Elk Hair Caddis, Royal Wulff or Adams up top, a Hare's Ear, Prince Nymph or Pheasant Tail underneath, and a small, dark Woolly Bugger for the resident char.

No named trailhead, put-in or parking area has been confirmed for Horsethief Creek itself. It sits within the broader Columbia Valley forest road network near Invermere, and Kootenay Troutfitters guides the wider Radium-Invermere-Fairmont corridor across lakes, rivers and streams, though no source confirms a program built specifically around this creek.