The exact lifespan of a tropical fish varies greatly depending upon the species. In general, larger fish have longer lifespans than smaller fish, and fish that give birth to live young tend to live shorter lives than those that lay eggs.
Goldfish are very hardy fish that can live for decades. Bettas, on the other hand, live for only about two years. Other short-lived fish include platys, mollies and swordtails, all of which generally live less than five years. Loaches, angelfish and bloodfin tetras commonly live at least 10 years,while convict cichlids have been known to live 20 years or longer.