Blue-Finned Elephant Tuna

A Blue-Finned Elephant Tuna (エレファント・ホンマグロ Erefanto Honmaguro, Viz: Elephant True Bluefin; 4Kids: Titanic Tuna) is a fish that comes from the South Blue and has elephant-like features. It is known as the "jewel of the sea" and it is supposed to be a miracle ingredient for cooking. It is classified as a type "A"; "Big Friendly"creature. It first appeared in Chapter 98 and Episode 51

History
In the original manga, Sanji bought one, while in the anime, Sanji competed in a contest against another cook, Carmen and won it. During the Laboon arc, Sanji prepared the fish for everyone while they were speaking with Crocus in Twin Cape. Usopp and Sanji were paying attention to Nami and Crocus's conversation while, unbeknown to them, Monkey D. Luffy ate up the rest of the fish, including the bones.

Another one has appeared in the Thriller Bark saga. While feeding Oars, the zombies realized that it was a salted fish that could kill Oars if he ate it : the fish was a blue-finned elephant tuna. The zombies got rid of it at the last second.

Another one has made its appearance in Episode 426. It was fished up by Luffy, Usopp, and Brook, but was carried off and eaten by a gigantic beetle called Boss.

Trivia

 * It was also seen in Unlimited Adventure and Unlimited Cruise that it could be caught as a fish.
 * According to Luffy, its nose was the best part of the fish to eat as he easily remembered when in doing so at Loguetown.
 * It has been seen later in the Grand Line a few times, including in Water 7.