redmouth

from The Century Dictionary.

• noun A fish of the genus Hæmulon (or Diabasis); a grunt. Also called redgullet, See Hæmulon, and cut under grunt.
• Having a red mouth or lips; red-mouthed: as, the redmouth buffalo-fish, Ictiobus bubalus.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) Any one of several species of marine food fishes of the genus Diabasis, or Hæmulon, of the Southern United States, having the inside of the mouth bright red. Called also flannelmouth, and grunt.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective zoology Applied to various fishes with a bright red mouth.