This is by far the best method I use for catching fish ( I have wrasses and it works on them). If your fish eat agressively i.e don't run away when you drop in the food, use a med size white plastic cup and drop a cube of food in it and hold it near the glass. Make sure all the pumps are off so the cube stays in the cup. If the fish aren't skiddish they will go in the cup after the cube. Quickly press the cup against the glass when the fish goes in and slide it out. I usually use a net when I have the fish in the cup to help keep it from jumping out (don't put the net in before you have the fish in the cup). This has worked on my wrasses and clownfish. Hope this helps