Re: NANFA-- Taxonomy Question about Notropis heterodon/Rasbora taeniata

Dave Neely (
Wed, 15 Dec 1999 08:37:28 CST


Rasborines have a symphyseal knob on the lower jaw (a bulb-like structure
that dovetails into a notch in the upper jaw). Look at your fish face-on in
the tank and you should be able to tell. In addition, if you can cacklight
the tank, you should be able to count anal-fin rays. Rasborines have a very
short anal fin, with only about 5 rays, whereas Notropis heterodon will have
7 or 8 rays. In addition, R. taeniata is supposed to have a yellow-red
caudal fin, in contrast to the clear caudal of heterodon.

Sorry, I'm just a fish systematist, and don't have any good husbandry info
for heterodon, but there are a bunch of other people interested in breeding
and maintaing heterodon for conservation purposes.


>Do you know if there is any way to tell a _Rasbora_ from a
> >_Notropis_,short of either pulling them out of the pond or >dissecting

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