that tank will stay where it is for now. i have bought a hood now and it looks great.... It's really work in progress.. i will eventually put doors on the cabinet and enclose it fully.
The other tanks are 4ft x 2ft x20in 300L and 2ft x2ft x2ft 200L
As for tha breeding pair of gouramis, they would stay in the 40L and fill the 8ft.
I also have a pair of blue rams and golden rams too that will go into the larger tank. I've found they are only aggressive between themselves, unless theyre nesting.
The ghost knive are a worry to me too. They havent worried the discus yet in the smaller tanks. but they can only get bigger.
PS i do have a few pics in my gallery. Feel free to have a look