Wise old soul. (CALLING ALL SA EXPERTS)

[CichlidFiend]

This is not your typical 'what can i put in my tank.' I was inspired by this video, you don't have to watch it to know what i want, but its wonderful if your attempting to recreate the amazon in your tank.
[YT]http://www.youtube.com/watch?v=TzzJU810AIk[/YT]
currently my 55 holds a sailfin plec, a trio of silver dollars, and a pair of pictus.
originally I wanted to simulate a flowing river or stream, with the pair of pictus as the centerpiece, but these guys are nuts, ive taken to calling them merry and pippin because they just generally cause chaos, scattering the school of SD's, hiding the algae wafers from the plec, etc.
Im looking for a species of fish that can live in a 55 for life, hopefully they dont grow larger than 10 inches, as the width of the tank is 13.5 inches, something that puts a lid on the pictus, a kind of gandalf for the tank.
Im considering yellow tail barracuda, crenicichla, but thats just because i know they can be easily found. It doesnt have to be a predator, just something more docile, ideally a pacu or GG but theyre just too large.

Are there any fish youve had experience keeping that you could recommend?

 

[ragin_cajun]

Awesome video!

 

[Pole]

the pictus will usually be last to be picked on,if u want a Gandalf maybe a cichlid but it could aggress everything else too. I suggest a separate tank for the pictus if they really annoy u

 

[Wrightt3]

Don't mean to be rude but the pictus are probably the smallest problem here. Sailfin plecs get big! too big for a 55, that's for sure and the dollars are shoaling fish that need groups of at least 5. Not only that but a 55 doesn't provide enough swimming space for a 4-6" active shoaling fish. If you were to rehome the plec and dollars then all your problems would be solved. Then you could add some sort of centrepiece fish or two to replace them. Perhaps a pair of some of the smaller pike cichlids in the 6-8" range? Crenicichla Proteus are nice.