Each fish picture clues a letter using Semaphore. When a card is flipped over, it usually gives the same image. The letters corresponding to the grid are:
CRGDOI ATLGBS IULPHH SRPCOA NEQTBN EUQFDF
However, the player finds that when they try to flip two of the same at once, the second one shows a different picture than usual. The letters corresponding to these secondary pictures are:
HBFNCK OGNUPO GLSUTQ AZMIDE KCIFQD TPHMRS
Most of these letters are paired up; read the ones that are not paired up to get the answer, BLAZER.