This three-tined fork atop a stout rod of 6-ft length appears to be a barbed military fork of some sort. 

However, its magical properties enable its wielder to cause all fish—including sharks and eels but excluding mollusks, crustaceans, amphibians, reptiles, mammals and similar sorts of non-piscine marine creatures—within a 6" radius to save versus magic (this uses one charge of the trident). 

Those which fail this throw are completely under empathic command, they will not attack the possessor of the trident nor any creature within 10-ft of him or her, and the wielder of the device can cause them to move in whatever direction is desired and convey messages of emotion, i.e. fear, hunger, anger, indifference, repletion, etc. 

Fish which make their saving throw are free of empathic control, but they will not approach closer than 10-ft of the trident.

Fish which school must be checked as a single entity. 

A trident of this type contains 17-20 charges. It is otherwise a +1 magic weapon.

Class Requirement. Cleric (Druid), Fighter (Ranger, Paladin), Thief (Assassin)