"You got some pink coral! This pretty piece can only be found in clear water!"
Pink Coral is a small obtainable treasure acquired within Phantom Hourglass. It is scattered across the various regions of the World of the Ocean King, and can be found at random. Link has the option of selling this item to the Treasure Teller on Mercay Island, or he can sell it to the Ho Ho Tribe, but only on certain days.