I have a 500l community tank with tetras and corydoras currently.(Angel Fish and plecos being added shortly) All the tetras seem to hang around in the bottom half of the tank. Below or just above the level of the plants. This leads to this part of the tank seeming crowded while the top half of the tank is empty. I was wondering if anyone had any idea to persuade the tetra into the top half of the tank. All i could think of was some big plants across the back maybe or some more frogbits I have about 1/2 sq foot at moment. Problem with frogbits was i was worried it will starve my other plants of light if i put to much in.