I have been to Think Fish and made up some stocking scenerios. I definitely wouldn't trust them. Their stocking levels are way out of line in my opinion. For instance, in a standard 29 gallon tank (18"x12"x18"), their stocking calculator says that 20 black phantom tetras, 20 zebra danios and 10 corys is a legitimate stocking scheme with normal filtration. To me that is terribly overstocked for a beginner, who is most likely the one to be using this site. When I changed it to an oversize external filter, te quantities can go up to 12 corys, 25 tetras and 22 danios. To me that is just too many fish to allow adaquate swimming room even if the filter and maintenance schedule is adaquate.