Ok. I would have at least one- two banks of tanks brackish for mollys ,Africa cichlids ect. That's good news on not needing any approval for meds. For orders let's say for example you order from segrest farms and can get sm fantail calico gold fish for .50 most stores do a mark up of 2.5 So instead of selling the fish for 1.49 sell it for 5.99 just pick certain fish that sell well that way you can have a buffer for fish that you lose or can lower prices of more expensive fish to help them sell. Also if you can do phone orders most the time the people will tell you if there are any fish you should avoid that week. Number tanks and make a schedule for the tanks brake up what needs to be done day by day. You can have it laminated get some dry erase markers so things can be checked off as they are done that way when you come in you know what needs to be done. I also wouldn't order any fish until you get everything under control. keep all the tanks 80° - 82° 74 is two low. a chart for sick fish is handy as well get you a binder and put what they have how to treat it how often to treat it and have it to where you can mark off when it gets meds. Have you gotten all the sumps cleaned out yet? If they are like a mars units they can be such a pain.lol do they have auto top off?