In the scientific method, Occam's razor is not considered an irrefutable principle of logic or a scientific result; the preference for simplicity in the scientific method is based on the falsifiability criterion.
Many freshwater fish average about 1 to 3 years of life. Some of the more popular species with this short life span include fantail guppies, swordtail platy, mollies, rainbow fish, hatchet fish, corydoras catfish, some cichlids, rasboras and tiger barbs. There are also several fish that live around 3 to 5 years, with proper care and feeding.
Depends on the type of fish and the type of care they receive (as well as luck). Certain goldfish and koi (among others like sturgeons, etc) can live for decades. I expect the fish I have (puffers & african cichlids) to live 8 years or more. It's kind of a shame when a fish that has a life span of 10 years or more dies in a only couple of months in the wrong hands. any where from 3 months to 5 years for tropical from 5-8 years for goldfish the koi can live between 100-150 years in good conditions. 6 years. depends what kind of fish!