A small tropical American killifish of fresh and brackish water.
（生活于热带美洲淡水或稍带咸味的水中的）鳉，溪鳉
Genus Rivulus, family Cyprinodontidae: several species, many of which are spotted
Origin
Modern Latin, from Latin, literally 'small stream'.
Definition of rivulus in US English:
rivulus
nounˈrivyələs
A small tropical American fish of shallow fresh and brackish water. Often mistaken for a killifish or topminnow, the rivulus is distinguished by its tubular nostrils.
Genus Rivulus, family Rivulidae: several species, many of which are spotted, in particular R. marmoratus
Origin
Modern Latin, from Latin, literally ‘small stream’.