Oh no, you accidentally introduced a fish into your tank with velvet, and now you are doing all you can to save your tank. Maybe you accidentally bumped into your tank and broke something off of it. Do any of these situations sound familiar to you? Mistakes are something all of us make in the hobby. However, with mistakes comes better knowledge about what we should or shouldn't do. I am wondering what mistakes you have made in the past and how they have shaped you into becoming a better reefer.