me·da·ka 
(mĭ-däkə)
(mĭ-däkə)n.
A small Japanese fish (Oryzias latipes) that is commonly found in rice paddies and is often used in biological research or in stocking aquariums.
[Japanese : me, eye + -daka, combining form of taka-, stem of takai, high (in reference to its large, protuberant eyes).]