Considering the tank is barely big enough for one of those arowanas fully grown I am not surprised there is problems. Like usual an unnatural tank with no decor,room to swim or things to break up the sight pattern so fish can feel more relaxed. Only owned an african aro eons ago for a short time due to it's feeding habits and lack of information on them at the time so it died within a couple weeks. Hence I said it MAY work with the other aros. For every video like that a person may find one where it works(too lazy to post one). All depends on setup,size of tank and whether the fish were raised together when small. Now that I have an asian aro you couldn't pay me to own an african one...Man they are butt ugly!
Due to your location I would only recommend a black arowana. Why?...Silvers-drop eye,jardini aggressive,african aro-butt ugly and appear aggressive from that video. Owned lots of black arowanas and they have all proved good for me together and with other tank mates.