1.
small animals
A counter for small to medium-sized animals such as fish, insects, cats, dogs, etc. Not used for birds or rabbits.
匹 is used for small to medium animals (fish, insects, cats, dogs, etc.) but NOT for birds (羽) or large animals (頭). Pronunciation varies: 一匹, 二匹, 三匹, 六匹, 八匹, 十匹. The consonant changes between ひき, ぴき, and びき.