I hate to be the one, but what you have is essentially a blood bath in the works. While everything may be fine now. In time when maturity sets in these fish will start fighting for turf to claim as thier own. These cichlids are not like Africans and calm down with over crowding. Quite the opposite in fact. You also have fish in here that prefer different types of water. The ones from South America want soft mineral poor low PH water. The ones from Central America want hard mineral rich high PH water. The Tapajos prefers a group of its same kind.
650 gallons may seem like a lot. But in the wild one of these cichlids as an adult would claim an area four to five times that area as it's own, not allowing any other cichlids in there. And not sure about the Channa, it may get big enough to outright eat everything else whole.
I would suggest picking out if you want the South American or Centrals and stick with them only.
Thanks for your valuable comments , you have a point in every article.
For fighting issue , there is no any "hard" problem for existing fishes , there was some of them like Vieja Zonatus or an almost full grown Oscar but taken off from the tank. In my former experiences over crowding seems solving this issue but i believe every fish has it's own behavior. So fighting and dominance directly related with fish's character. I am observing them and if i see any over aggresive attitude quickly taking precautions
Yes their PH preference is different but not has huge differences . Sudden PH changes are much more lethal than unsuitable PH level. So i am trying keep the PH Level stable
I would like to take off Tapajos and 1 Vieja Breidohri that i see they are not happy in the tank but i could not catch them
My Channa is Channa Pulchara , Pulchara's max growth size is about 20-25 Centimeter and more friendly than other Channa species. But even so , i tottally agrre this tank is not his habitat
I am not only keeping them for my visual pleasure , i am also trying to make them happy & healthy. So if there would be any undesirable situation , i could do whatever needed