Can I just point out that different goldfish varieties COULD be considered breeds but that would NOT make them different species. Just like all dogs - whether an irish wolfhound or a chihuahua - are the same species.
Wilder, I would disagree. It would be much simpler if we used the scientific names. The scientific name is just the same as a common name but there's only one valid one (as opposed to several, if not hundreds, when it comes to common names). On top of that, the scientific name of a fish can give you clues as to its behaviour and requirements. True, the scientific name tends to be longer, but at least you don't need to remember 20 different ones
It is precisely this issue that I keep coming across with gouramies - three-spot, opaline, gold, blue, platinum, lavender, cosby, even pearl and lace, I have seen used for the same exact species - trichogaster trichopterus. Similarly, colisa chuna/sota, colisa lalia, colisa labiosa and colisa fasciata are often found with the same or over-lapping common names. Or you can take a more extreme example - the giant gouramies - orphronemus goramy and colisa fasciata - where getting them mixed up due to the common names is a little more hazardous as one gets to 30" while the other stays around 4".
For non-gourami examples you have only to look at all the common names given to different strains of guppy or platy and notice how many people seem to think of them as seperate species. Then this goldfish example is another prime one. And lets not forget the difference in common names between countries - black skirt as opposed to black widow for example. Scientific names remain the same regardless of where you live - which also makes research and correct identification easier.
Basicaly, the common names realy annoy me but we're all entitled to our own opinion
Sorry for the rant BTW
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