Crossword puzzle clue "fishy controls"

FIN, to equip with paddle-like structures

(French) a balancing flap on an aeroplane

CHECKREIN, a short rein looped over the check hook to prevent a horse from lowering his head, aka a bearing rein

(Nahuatl) the (dried) red pod of a Capsicum pepper used in sauces, relishes, etc., and made into a hot cayenne, also CHILI, CHILLI