silver dollars are fine with nearly anything that is peaceful. aslong as its not discus that can have heart attacks when the move.
I had mine with plecos, bristlenoses, khuli loaches, clown loaches, black ghost knife, choc ghost knife, angels, kissing gouramis, red tail shark, barbs ( even though they would nip them every now and then), nad even a clown knife.
So i hope this helps.
Also only keep one type of each shark as the will bully them and or each other to death.