i have a 75G tank that currently has a clown knife(getting rid of)a senegal bichir and a baby jardini arowana. i was re-thinking my decision on getting the jardini since it won't last him forever. i am getting 2 more senegals for sure and was wondering about what fish i could get that would roam the middle to top region of my tank? i was thinking on maybe some discus since bichirs can handle wide ranges of water parameters, but i'm not sure...