狗

只 is the counter for dogs, cats, birds, and most small animals: 一只狗, 两只猫, 三只鸡. 个 is the lazy default you use for people and junk objects, so 一个狗 sounds like you shoved the dog into the wrong drawer. Nobody will misunderstand you, but it immediately marks you as a learner. Learn 只 early and you stop guessing. For pets, 只 is safe almost every time.

The one exception worth knowing: 一条狗. It is not wrong, but it is heavily marked. In everyday speech about a real pet, stick with 一只狗.

English 'puppy' has an age rule. 小狗 does not. A ten-year-old chihuahua is still 小狗, and so is an eight-week-old labrador. One word covers both, which is why learners get confused when their Chinese friend calls a fully grown dog 小狗. Meanwhile 小的狗 is understandable but reads like a photo caption, not a name. Chinese builds animal names by sticking 小 on the front: 小狗, 小猫, 小鸡, 小马.

This exactly matches the opening rhyme of the story: “小狗小的狗。” (A puppy is a small dog.)

Chinese has used 狗 for centuries to mean low, sneaky, or servile. 走狗 is a hired thug, 狗腿子 is a bootlicker, 狗东西 is a straight curse. So 你真是只小狗 dropped on a coworker reads as a jab, not a compliment. That is the opposite of English, where 'lucky dog' is warm and 'puppy' is cute.

The word is not banned, though. Self-mocking slang is everywhere and totally fine: 单身狗 (single), 累成狗 (dead tired). 热狗 is just a hot dog, 狗年 is the Year of the Dog, and 狗狗 is affectionate for an actual pet. Rule of thumb: 狗 about yourself is funny, 狗 about someone else is a fight.