Ceramic ring/aquarium filter 1.Used in rearing pond as a filter 2.provided with high filter character filter medium consisting of porous ceramic pipes suitable for use in freshwater and saltwater aquariums. *Double features filter medium, can be used as a mechanical prefilter medium for coarse particles or as a biological filter medium. As prefilter medium, protects the biological filter material from rapid silting. *The hollow structure provides ideal conditions for beneficial bacteria, whilst at the same time allowing excellent rates of water-turnover. *Highly efficient surface for beneficial bacteria to colonize.