Probably where the animal interfere with the work? Imo doesn’t matter what kind of animal you bring as long as it’s not a nuisance. The line isn’t drawn by species but behaviour
I.e got a chill duck that just hangs around that’s fine. Hyper puppy that chews on cables and pisses on all the plants, not so much. As for a hippo you would have to check the buildings structural integrity.
The people in the tanks needs to agree with him then ;)