That was a joke. Scats need high-end BW--specific gravity (measured with a hydrometer) around 1.010-15, when young & closer to marine conditions (1.018-23) when adults. Scats are very messy fish--I wouldn't keep more than 2 in that 55, as they will grow the size of a dinner plate. Weekly 50% water changes are necessary, till you reach marine SG & then you can add live rock & a protein skimmer for better water quality & less water changes.