A Swordfish certificate is a certificate that is obtained by exchanging five swordfish with Niles at Draynor Village market, Seth at Brimhaven or Orven at Fishing Guild or by smashing strange barrels. Swordfish certificates are stackable and each one can be exchanged back for five swordfish by talking to their respective certer. Because swordfish are not stackable and players can only trade twelve items per trade screen, they are often exchanged for certificates so that they can be traded easier and faster.