Hello! I am looking to invest in a 300g aquarium with a black arowana and 2 motoro or black diamond stingrays. My idea was to add 6-10 discus with the arowana as tankmates. Would the discus be too small for the black arowana? I would be okay with removing the discus when the arowana gets really large to prevent overstocking. If I didn't remove them do you think it would be overstocking? Any arowana with discus experience would be greatly appreciated. Thanks!