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Crossing Endler's Livebearers and Guppies


Dear Aquaworld,

I have been raising guppies for about a year now.  When I first bought the guppies I also bought endler's as well.  Now the aquarium store I had bought them in said that endlers and guppies cannot breed and make babies.  But it seems that some of my new babies look a little bit like both and some of my males are a little bit smaller and their fins a little bit different than their parents.  Also, after reading some articles online I have found out that they can breed.  My main question is...Is this new generation of endlers/guppies also able to breed and have babies?  I only ask because one of the articles I read said cross breeding them make sterile fry so I just wanted to make sure.

Thank you for your help.

Bristol, PA USA


Dear Lindsey,

California Tiger Endler's Livebearer

California Tiger Endler's Livebearers are one example of what can be developed when you cross Endler's Livebearer with a Guppy.

Yes, as you have found out first hand, guppies and endlers will cross and produce offspring.  The offspring are not sterile and can be used to develop more guppy/endler varieties.  Because of this, the Endler's Livebearer is not its own species, and is actually just a unique guppy variant.  Ichthyologist often make the mistake of giving new species status to fish that are just variants of an already named species.  Ichthyologist often forget there is more to giving a fish new species status than just looking at physical differences of shape, size, color, and bones.  If the fish can cross and produce viable offspring that can reproduce and produce viable offspring, they are the same species.  That is the undeniable test of what makes a fish a separate species.

Tony Griffitts

Published - 20080906