A vertical scale on a spring balance reads from 0 to 200 \rm{N}. The scale has a length of 10.0 \rm{cm} from the 0 to 200 \rm{N} reading. A fish hanging from the bottom of the spring oscillates vertically at a frequency of 2.05 \rm{Hz}.
Ignoring the mass of the spring, what is the mass m of the fish?