I just got a Silver Dollar and a Red Bellied Pacu. The Silver Dollar is about 1 inch long, and the Pacu is about 1 ½ inches long (both babies). I’ve got them both in my 29 gallon tank, for now. I have an oscar , that is 8 ½ inches long. In a 75 gallon tank. I was wondering… in time, when the silver dollar, or the pacu, get bigger, do either of them make good tank mates with an oscar??? I realize that both the Silver Dollar, and the Pacu get very big, and are going to need bigger tank!!! I was just wondering if I could slip one in with the oscar??

Silver dollars don't get particularly big, probably no more than 6 inches so make very good tankmates if tank size is limited. Pacu on the other hand get huge, up to 3 feet, but normally only in the wild. However, pacu could easily reach 18 inches or more in captivity so would be too big for most peoples tanks. If I was you, I would forget these fish, get rid of it and find something more suitable.

Silver dollars are best kept in groups. Get rid of the pacu and get another 2 or 3 silver dollars