Fish (lat. Pisces) are animals that spend all of their lives in the water and are cold-blooded with the exception of Tuna family and the Mackerel shark family, most of them breathe using gills, have backbones, have a scaly skin, and have various fins instead of limbs.
Fish are an important resource for humans worldwide, especially as food. Commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean.