Quote:
Originally Posted by rs79  Scheel ("Rivulins of the old world, TFH Press, 1968") has a good write up of Mycobacteria. The authos makes two main points: 1) it's in ALL fish, period. Only when they're under bad conditions does it go anywhere. 2) Hard alkaline water keeps it at bay. It begins to be a real issue in soft acid water. |
Perhaps the more virulent strains were not around or well-known back then. I have hard alkaline water and so does Diana.
Quote:
Originally Posted by rs79 As for Endlers, although they've recenlty been described as a separate species there is still some consensus that they're just a population of guppies. The jury's still out on this one. |
I believe that they are a separate species. There are just too many differences. They don't hybridize in the wild. They have different gonopodial structures and the courting behavior is different. Pure Endler's also do not jump - guppies do. When they do hybridize, you get an amplifying of phenotypes of the parents rather than something in between. I'm sure there's much more but it all points to speciation. There are probably fewer differences between species of mollies, which can also produce fertile hybrids.