抄録
In general, it seems to be very important method to visualize eddies formed around a fish in order to investigate the fish propulsion, but only a few methods have been reported by this time.
In this paper, three methods of visualization are shown. One of them is a tracer method and the others are methods making use of the refraction of a light which passes through stratifies fluid. After pouring water into the box made of clear plastic plate with 5mm thickness, about 30% sugared water mixed with Chinese ink is slowly injected into water along a slender bar.
The light must be situated in the opposite side of the camera.
Fishes used in this experiment are a carp, a goldfish, a dace and a mudfish.
