A guide has an open end and a finger structure preferably of a shape memory alloy. The guide is run in small-diameter configuration through a restriction with a fishing tool, such as an overshot, above it. Once through the restriction, power to heaters on the fingers takes the material past its transition temperature to allow the guide lower end to fan out and surround a skewed fish that is in a slanted position and leaning on a wall of a surrounding tubular that has a larger dimension than the restriction. The bottomhole assembly is then advanced until the fish is captured by the fishing tool and pulled out of the hole. The fingers are forcibly retracted as the assembly is pulled back through the restriction. The guide can use retained fingers with an outward bias to flare out after passing through a restriction, thus acting as a fish guide.