Im answering this Q off my primitive knowledge of redtalied sharks, almost the same but only the tail fin is red. They both have identical personalities. Everything i read about them tell me, highly aggressive. my book tells me keep them in a tank with lots of space and fish with similar size, these sharks are known to chase other fish away from food and starving them to death. I have never dealt with flying fox's but from the pics I see, they seem mighty small. My educated guess would be this is a risky situation. They might be small enough and as long as your tank is big enough to hide and live pretty peacefully in a rocky,planted setup. but if the tank isnt that big and there arent alot of nooks and crannies, i see a big problem. I had 3 or 4 redtailed sharks in my day and they were always aggressive nibbling and pecking at my other fish.
EDIT: I forgot about your dimensions, 1 flying fox in a 30 gallon, sounds ok, as long you have the rocks and plants to break up the tank up and seperate them if hes gets bullish. provide hiding places.
