Toad

I added this pic to her page

Hogwarts allowed students to bring pets to Hogwarts as long as they fall to a specific criteria of animals.

Harry had Hedwig which to the wizarding community owls are a practical pet for mail delivery. Hogwarts had an Owlery so when not with Harry or in her cage at Gryffindor dorms, she was likely in the Owlery with the other owls.

Scabbers, Crookshanks and Trevor were pets to other students and half the time we didn't know where they were.

We don't know how many students in Hogwarts had pets, but pressuming half of them have at least a toad, cat or rat you'd think there would be more animal droppings, or disputes amongst students on pets hunting their pets, or Neville not being the only one looking for their pets. Given students have class to tend means they cannot observe them all the time so where are all these pets in Hogwarts?

I pressume the Hogwarts house elves clean up after them at least given no droppings seen in the corridors but still doesn't explain where the pets are or who looks after them whentheir owners attend classes.