There are several fish species that have big mouths. Here are some examples:

• Napoleon Wrasse: Also known as the humphead wrasse, this marine fish has a big head and big lips.
• Giant Gourami: This species of gourami fish has a big mouth and should not be confused with the smaller kissing gourami.
• Sarcastic Fringehead: This small saltwater fish has a massive mouth that it uses to protect its territory and love den.
• Bigmouth Buffalo: This fish is the largest North American species in the sucker family and has a terminal (forward-facing) mouth.
• Bigmouth Sculpin: This fish is found in the Gulf of Alaska to Canada and Northern California and has a large mouth.

Its worth noting that some fish species have big lips instead of big mouths, such as the koi fish and the harlequin tusk wrasses.