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.
Short Lifespans. Killifish are among the aquarium fish with the shortest lifespan. They generally only live a year or two. Bettas are not far behind, averaging only about 2 years. There have been documented cases of Bettas living 5 years or more, but that is not the norm.