How do I catch Leprechaun or do I need to in order to complete that quest?

You dont need to catch him or kill him. You cannot complete this quest if you are still in the main area (before the Temple of Isis). Near the end of the Isis temple you will go up and talk to Kerah. Swim up and out of her temple and look around, you will meet the little green guy again here. He will give you a needed item to complete the quest and then he will disappear forever.


Vorrin

Thanks Vorrin.