Sorry slt, (what the heck is a monos anyway?), one guess left.
Let's review everything, you folks will slap yourselves when the answer comes if nobody gets it..
I am a peaceful S.American characin, I like a large tank with nice sturdy plants because I will eat the delicate ones. I am mainly a vegetarian, so I like vegetable based pellets, I come from the Amazon. When little in the pet store, novices could easily mistake me for a silver dollar,(one of my closest relatives), or even a pacu or piranah. I have a red anal fin....
Good luck everyone....