There are about 30 fish with names beginning and ending with the letter K. examples .... KA'K a far-eastern jack or pompano. KA'NINK an African freshwater electric catfish. KALIMANTANIA LAWAK a freshwater tropical minnow. KROPTERUS LIMPOK a freshwater Indonesian sheathfish. Others include Kaapse Kraaibek, Kabak, Kaerrak, Kaitailik, Kajok, Kakilrok, Kalushak etc. etc.
You could also say that any cooked fish is likely to begin and end with K, as in Knife and forK.