Pet Lizard with Parrot?

Will a Red Tail Black atoo get terrified of a larger lizard such as Tegus / Iguana / Monitor / Frilled Dragon ? Will these Lizard exclude Iguana come and bother my atoo ? I prefer maybe a Medium to large size lizard as I do not really like smaller lizard as I am afraid that they are a bit fast and fragile , while a larger lizard will be slower and stronger