I'll try to let the pics speak for themselves, but here's a brief background. I've had the oscar for about 2.5 years now and it has gone from 1.5" to almost 13" now. I got the severum last summer at around 2" and it is now between 6" and 7". The P. Gibbiceps is about 7" and was purchased at around 1.5". The P. Joselimaianus is a little over 5" but hides most of the day. Currently there are 6 Bolivian Rams at about 2" each but I will likely add 2 or 4 more, and 14 Giant Danios being used as dithers (this is the reason my title has "South American" in quotations). The Oscar grew up without being fed live foods so he doesn't bother chasing the smaller fish, I'm lucky I guess. Anyways, here are some of the most recent pictures of them all. Sorry, the lighting washed out some of the pictures.