I’m going to purchase a 10” black arowana for my 500 gal display tank. I have the opportunity to get more than one. Would two work out or would I need three to make multiples work? Or should I just play it safe and stick with one? The tank already has a Black diamond stingray and I’ll be adding two more stingrays. Filtration is not a concern, my filtration is sized for a heavily stocked 2500 gal system and I have a continuous drip water change system. Thanks in advance.