Aging changes in the heart of a poeciliid fish, the guppy Poecilia reticulatus.
Histological surveys of the hearts of guppies Poecilia reticulatus throughout their lifespan showed no aging changes until the fish were three years old. In younger fishes the hearts were healthy, even in three individuals with "wasting" disease, where there was considerable loss of muscle throughout the body. There was a loss of muscle fibers in the ventricle in old fish, and deposition of collagen in the bulbus arteriosus. Guppies of three years and older also had a marked accumulation of melanomacrophages in the atrium. It seems unlikely that degeneration of the heart is involved in mortality of guppies in the wild.
D000375:Aging; D000818:Animals; D005260:Female; D005399:Fishes / Q000033:anatomy & histology*; D006321:Heart / Q000033:anatomy & histology*; D006325:Heart Atria / Q000033:anatomy & histology; D006352:Heart Ventricles / Q000033:anatomy & histology; D008264:Macrophages / Q000166:cytology; D008297:Male; D008544:Melanocytes / Q000166:cytology