The development of larval fishes is a chronically understudied, critically important field, which offers broad insight into a defining period in the life history of fishes. Examinations of development shed light on the behavior and ecology of fishes at a stage wherein they are difficult to observe directly. We cleared and stained 36 specimens of the soft sculpin, Psychrolutes sigalutes, in an effort to link morphological development to preexisting studies on their behavioral shifts with growth. Rapid development of feeding structures suggests a fish that quickly grows into a highly capable hunter, well-suited to its lengthy transitional feeding period in the plankton. Given the intense focus of development on hunting, we believe that transforming P. sigalutes may be the apex predators in their habitat, possibly responsible for the top-down control of local ichyhtoplankton
