How does the craft mesh alone work for you as a divider? Never seen it done without the report spines on the sides too, so I'm curious :)
It works fine. I just pile gravel up on each side, and tape the top to the side of the tank. I would have done the report binders, but I already had the tank filled. I did this with my 10 gallon as well, but I sewed together two layers of craft mesh and added a black plastic insert so my fish can't see each other. The 10 gallon has two males and a female in it, and I don't want them flaring at each other all the time. lol
Beautiful betta tank! Was that a Corydoras catfish I saw with the goldfish? Personally, I would either take the cory out or take that goldfish out and add more cory cats. They like to be with their own kind in groups of at least 4 and really can't be housed with goldfish. Plus, they need a heater. This is just some friendly suggestions from a fellow cory cat owner :)