Caviar fish is a type of fish that produces roe, or eggs, which are used to make caviar. The most popular types of caviar fish are Belugas, STURGEON, and SHAD. Belugas are a species of STURGEON found in the Caspian and Black Seas, and they have seven letters. STURGEON is a large fish found in the Atlantic, Pacific, and Mediterranean oceans, and it has eight letters. SHAD is a type of herring found in the Atlantic Ocean, and it has four letters. Finally, BELUGA is a type of STURGEON found in the Caspian Sea, and it has six letters.