मासा हा पाण्यात राहणारा जलचर प्राणी आहे. मासा हे मानवाच्या दृष्टीने पौष्टिक अन्न आहे. यातील प्रथिने शरीराला पोषक आहेत. ती कॅल्शियम, फॉस्फरस व लोह यांसारखी जैव मूल्याच्या दृष्टीने महत्त्वाची असणारी

A fish is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. Most fish are cold-blooded, their body temperature varying with the surrounding water, though some large active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communicate acoustically with each other, such as during courtship displays.