Sanemi has a Japanese Rhinoceros Beetle, Mitsuri a rabbit, Himejima likes cats, Shinobu has goldfishes, Tengen has mice, Giyuu was once bitten by a dog in the ass so it’s impossible for him, Tokito can’t have pets because his crow gets jealous.
Fundamentally, as long as it is a girl (and it doesn’t matter what kind of girl), he becomes aware of them and gets nervous. However, he’s not very good with girls like Aoi, meaning, those who nag a lot and act like a class president.