Squirt appears 75 times at rank 1439 on male pets, applied almost always to small dogs where it functions as affectionate size commentary. It's the naming equivalent of calling the smallest player on the team the biggest nickname, and it is done entirely with love.
Size Names and Affectionate Irony
Squirt belongs to a category of size-descriptive nicknames that pet owners apply with genuine affection: Tiny, Peanut, Squirt. These names are statements about physical scale delivered warmly. On a tiny dog, it's accurate; on a larger dog, it becomes ironic commentary the owner is clearly comfortable with.
The Pop-Culture Layer
Squirt is also the name of the baby sea turtle in Finding Nemo — the enthusiastic, surfing juvenile who greets Crush with unfiltered enthusiasm. That association adds animated warmth to a name that might otherwise read as purely descriptive. Owners of the appropriate age who grew up with the film may be drawing on that reference. Nemo and Crush occupy adjacent territory. Compare also to Chihuahuas and compact terriers where the name fits most naturally.
The Counter-Reading
Squirt is a name with a ceiling. It works perfectly on a small, lively dog and creates pleasant cognitive dissonance on a large one. The challenge is it can read as a placeholder nickname rather than a considered permanent name. Most owners using it have committed fully, which is the only way to make it land.