life span of guppies

If they are happy and healthy, temperature, feeding and all, 2 to 3 years is about right!
 
it depends a lot with breeding strains and whatnot.

the 'wild', or feeder type guppies, often will not live past 2 years because of the excessive inbreeding that happens over and over and over in the closed breeding systems.

fancy guppies may live to be 3, or even 4 years old if they are bred from separate strains.

and of course, optimum tank conditions for as much of their lifespan as possible will help improve this. :)
 
I think you'll find 2 to 3 years to be about average for a guppy. You can extend this by not letting them breed, that takes a lot of energy from them, and by maintaining high quality water conditions, and a good variety of food. You're not going to squeeze more than another year or so out of most guppies though.
 
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