Idk what a flow knife is. Since you live in Florida I would get some fancy plecos. Common get to big then start making a lot more mess. I would put the larger angels in there and leave the small ones to grow. Idk if you want snails but I dislike snails. A catfish would be nice to have, I have a RTC and plan on getting a TSN. You should get a jardini arowana as well. Do you plan on leaving all the fish in there for the rest of there life? If so I would make it big as possible and take time to make it perfect. Send me pics of how and where you're going to make it.