Fish Tank Square Ring Feeder Station Floating Food Float Aquarium Feeding Plastic Color: Blue Material:Plastic Round size:outer Dia=7.5cm/2.95"; Inner Dia=5.5cm/2.17". Square Size:Outer L*W=10*10cm/3.94"x3.94"; Inner:8*8cm/3.15"x3.15". The fish feeder is suitable for feeding flake foods and other floating foods. Put foods into the circle, it will prevent food from floating around.