What's The Difference Between Dry Type Floating Fish Extruder And Wet Type Extruder For Floating Fish Food?

What's the difference between dry type floating fish feed extruder and wet type floating fish feed extruder equipment?The biggest difference is the wet type fish feed puffing machine need a steam boiler while the dry type aquatic feed  extruder doesn't. In this case, the dry type extruders for fish food is cheaper than wet extruder, and the feed pellets made by wet type pellet extruder is much smooth and with better quality.