Fisher Tiger, known as the Adventurer, is the original leader of the Sunny Pirates. Several years ago before the current storyline, he climbed up the cliffs of the Red Line with his bare hands to Mariejois, and attacked the holy land to free the Fishmen slaves there from the Tenryuubito. While he hated humans, Tiger did not discriminate when it came to slaves and thus also freed slaves of all races there as well. Among these other slaves were Boa Hancock and her two sisters.
With the Fishmen slaves he freed, Tiger changed the shameful hoof mark branded on them signifying slavery, into a symbol of sun and took them in. With them, he created the Sunny Pirates.
At some point in time however, Fisher Tiger somehow died and his command of the Sunny Pirates was given to Jinbei.