The Regal Dottyback wards Corrupted Ghoulfish from the water around you and increases your chance to find Queen's Lurefish by 100%.
Throw this fish back into the water for and gain a stack of Royal Chum, protecting the waters around you from Corrupted Ghoulfish and increasing the likelihood to catch Queen's Lurefish for 30 sec.
Throwing multiple Regal Dottyback can extend this buff up to 10 min.