I have a amazon themed tank. And I currently have 3 hujeta characins, 1 redtail payara, and one senegal bichir that is a little out of place. i am looking for a middle level swimmer that would make a good tank mate for my other predators. I have tried a couple of red tailed barracuda's (falcatus) but i can never keep them alive. This fish could not get any longer than about 12-15'' cause my tank is only 18'' in depth. The fish would also have to to well with live plants. Ok now with all the constraints what would you get. --------thanks in advance for the idea's