Hey Alex,
Yeah that's right, I love silverdollars!
Right now I am keeping the Myloplus rubripinnis (4), Metynnis maculatus (7) and Metynnis altidorsalis (6).
But of course they are not all in this tank.
Two do have some wounds that's true.
You gotta imagine their former tank as a tringular tank with a giant piece of driftwood in the middle, leaving no space to roam for them.
It's been placed in an office and since they act skittish to movement they don't know they most likely crashed into the driftwood and the glass.
Yes the diet is very important, I am feeding them frozen food (bloodworms), smelt, fresh cucumber/zucchini, arowana pellets and pellets for herbivores.