well 100g will cause all kinds of problems for a silver as it grows so 6'x2'x2' (LWH) would be an absolute min size for a single silver .. if u keep multiple aro's in 1 tank u need 6+ or a mated pair. and i agree skimmer would be a wast of $$... i wouldn't go with a sump or wet/dry ... i currently have a 2 1/2ft silver in a 6x2x2 tank an i run 2 filstar xp3 canister filters .... as far as tank mates go any thing that stays at bottom an wont fit in his mouth ... some aro's wont let any other fish in there tank some will .....
