Striped killifish

The striped killifish (Fundulus majalis), also called the striped mummichog, is a North American species fundulid killifish. It lives in salt and brackish waters in shallow coastal regions from New Hampshire to Florida. It exhibits sexual dimorphism, with the males having vertical black stripes and the mature females having horizontal black stripes along the sides of their silver-colored bodies. Juvenile females have vertical stripes, however, and one or two vertical stripes remain at the end of the tail even on adult females. The striped killifish reaches lengths of 6 (or occasionally 7) inches. In Feb 1916, Popular Science Monthly had a news article on research being done by Professor S. O. Mast of the zoological department of Johns Hopkins. The professor was studying the Fundulus majolisis and noted their ability to survive the draining of ocean tide pools. These fish would swim in and out of the tide pools on regular intervals, somehow knowing when to swim out before the tidewaters drained from the pools. If for some reason the outlet of the pool were to close off as the tide went out, the fish would quickly swim around the tide pool randomly looking for an alternate escape route.