Top Quality Koralia Slim - skim Protein Skimmer. Hydor USA - Koralia Slim. Skim Protein Skimmer Nano Sim Protein Skimmer for aquariums reefs for the well. being of nano and mini reef aquariums. Up to 65G. designed for surface water intake, the highly efficiant slim. Skim and nano. skim are compact and have magnet. suction cup support for free positioning, multi. venturi impeller technology for micro. bubble production and easy adjustable air control and foaming level.