Ph isn't that critical that its what is recommended, its more important that the Ph is constant. My Ph is at 7.6-7.8 in my amazon tank and my baby Pbass are thriving. Onto the subject of growth, at 2 years old and only 24" that arapaima's growth was being stunted big time by only having a 240 gallon tank. I have a 240 gallon tank and you would need to move that fish to something much much wider if nothing else after probably 12". At the dallas world aquarium they have some that are about 2.5yrs old and over 4ft in length. I've also heard from many people that this fish grows 3" a month give or take a little, so it grows like a red tail catfish but doesn't slow down after 2ft. Feeding bloodworms or krill something thats high in protein would be the best bet over feeders if possible. ~Trent
