Lemon tetra come from the north of Brazil (Rio Tapajós, etc.) so I think they would be intolerant of a cool period
G. gymnogenys group are more elongate, sexually dimorphic and mouth brooders, and rhabdotus group are monomorphic and substrate spawners. They are almost always found together in nature. G. gymnogenys-type like the current of the main channel and rhabdotus-type do not, preferring calmer areas. The gymnogenys group contains G. gymnogenys, G. labiatus and an assemblage of G. cf. gymnogenys. The rhabdotus group contains G. rhabdotus, G. meridionalis and an assemblage of G. ex-meridionalis (like G. n.sp. "Norte"). On Felipe Cantera's site (AqvaTerra) G. n.sp. "Norte" is G. n.sp. "Sequeira"honda237 said:What is the difference between the two groups?