Are there any differences between the pets other than aesthetics?

Question

In Torchlight 2 there are something like 6 pets to choose from. Are these pets any different in ability or is it just an aesthetic difference?

Answer 1

According to this wiki, all pets are equal.

However, different fish produce different properties when fed to your pet.

Answer 2

Yes, as I came across. There will be times when you get gold or items dropping at a location where you or your pet on foot can't go.

A flying pet can easily go to that place Shift + Click to pick that for you.

Also, when you're on stairs, your ground pet will travel up and down stairs to kill monsters. Whereas a flying pet can fly over stairs (on aggressive mode) & clear the location for you.