locate the fin on the side of the fish .go about 2-3 scales back or the width of 1 finger slide the needle in under the scale then stand it up . then push it in with a short quick jab .put the fish back in the tank and gentle sqeeze the air out. if it is in the right place you will be able to see air escape out if not repet process--- it does work as i have saved several fish this way as a tournament director----- to get a good needle you should go to a vetenarian and get a good gauge needle that will work as not to get plugged up --- hope this helps. just trying to put it in laymens terms