Brook Trout
Salvelinus fontinalis
- The body is olive-green covered with pale yellow spots and distinctive red spots rimmed with blue halos. No other common trout has this exact combination.
- The lower fins (pectoral, pelvic, and anal) are orange with a clean white leading edge followed by a black stripe. Look for that white-then-black border as a quick field identifier.
- The back and top of the head show a worm-like pattern of wavy markings called vermiculation. A maze of lighter squiggles on a dark olive background that no other trout shares.
- The tail fin is more square and less forked than most other trout, which is why anglers have long called this fish the 'squaretail.'