Well first of all african arowana is not really a true arowna species. It's more related to the arapaima as they belong to the same family. The old literature added them to the true arowana species but no longer belongs to the same family. Same goes with arapaiamas.
Here are some tips if you want to start keeping one. Don't buy any small afro aro as they are very sensitive and get hungry very fast when smaller than 4". Best to get them at 4-5 inches or much bigger. Fatten them up by feeding bloodworms or any plankton type foods. Feed almost every time you check it out as they have a very fast metabolism and if they lack food they die slowly of starvation and most cases of death are dying from starvation. Once it start to build up some fat reserve try to train it to eat other foods as you can now start the starving method by not feeding for 3 days but no longer than that. The bigger the fish the longer it can starve and still do well. You can try some pellets by crushing them or chop some prawn or shrimps to very very tiny pieces. Or same thing with fish fillet chop to small pieces. Once it start to take those foods, you can now forget about the bloodworms or blackworms as they are very addicting to fish and when the afro aro grows it may need more than those worms. So you will be spending more if you're still stuck feeding those worms. Once it gets up to 12-15"+ it will take floating aro sticks even without crushing them. Growth rate will get even faster and it will gain a lot of girth with that diet.
Afro aro in a comm tank, they can be very aggressive and will chase other bonythouge fish especially true arowana species. Will even pick similar body shape fish such as snakeheads or pikes. Will also won't back down from attackers unless it's much bigger or it got beaten up badly already.