Just curious what your stock is and how big your tank is just thinking about future ideas thank you.
I haven't had them,but they are semi-aggresive I wouldn't put more that 1 in a 30 gallon.
How big is your tank or will your tank be? They do well with most bottom feeders and peaceful tetras. They generally do well with livebears as they like the constant food source from the fry if that doesn't bother you. Definitely no nippy fish and no aggressive fish IMHO. They are considered semi-aggressive but they really have no way to defend themselves because their teeth are back in their throat and they can't close their mouths. That pretty much makes them incompatible with other aggressive or semi-aggressive cichlids (tho some people have done it successfully, I haven't tried). Small fish are fine as long as the Parrot can't fit them in their mouths. Schooling fish do well. It kind of all depends on what size tank you have as to what will go best with them. The more room you have the more options. Even a near species-only tank, with a few parrots and some cories for movement and cleanup is a beautiful set up but they do need a lot of room just for themselves.
Right now I have 1 in my 55.I used to have 3 untill an ich infestation killed my oldest 2. The oldest I had for about 4 years the other I had for 2 years alls I have left is my youngest one that Ive had for about 6 months. Im diffidently getting another, haven't decided if i want a 3rd or something different. I rearnged the tank and did a good cleaning and water change just thinking of some ideas before i go and buy anything and while i make sure the ich is 100 percent gone.
I had 2 in a 55 for 7-8 years. I will say tho that they started with an angelfish, a small school of something I can't remember (top level swimmers) and a school of cories. Eventually they got huge. Talking softball size. After about 2 years or so I moved the angelfish out to reduce the bioload a bit and let the upper level school die off naturally. I maintained the cories in there and they always did well together. So I wouldn't add more than 1 if u can resist because they will grow to be quite hefty and 3 will definitely outgrow your tank of you want more than 1 species in there. They are great fish tho, I just love them. I am currently cycling a 75 that will be for parrots when it is done, I'm itching for it to hurry up and finish!