What would be an optimal sized stream tank for some darters and dace? I'd like to add another tank to my basement this spring and since I built my 600 a smaller 100G or so would be a breeze to build. Obviously a long tank since it will be a stream tank. We are about to go through inventory in 2 weeks so we will be throwing out a lot of glass around 1/4"-3/8" of various sizes.