gerardinus guppyi

from The Collaborative International Dictionary of English v.0.48

guppy \guppy\ n. [Named after R. J. L. Guppy, who brought
   speciments to the British museum. --RHUD]
   A small freshwater fish of South America and West Indies
   ({Lebistes reticulatus} or {Poecilia reticulata}, originaly
   called {Gerardinus guppyi}), often kept in aquariums; also
   called {rainbow fish}.

   Syn: rainbow fish, {Lebistes reticulatus}.
        [WordNet 1.5]