I cant stand parrots and oscars. It must be because I feel like alot of people that dont know what they're doing buy oscars and they are the cliche monster fish. Parrots are just useless to me. They seem manufactured.
i dont like goldfish, big hump headed fish, im starting to dislike cichlids now they just seem a little boring, i dislike bettas, oh and birchirs they dont interest me, hmmm what else....i think that about it, oh and big puffers too (i think thas from constantly catching them while fishing in the ocean lol)
BUT i love natives of Australia and the US, so cool and snakeheads.
Bettas are at the top of my list. They don't really do much, a lot of them have such long fins now all they can do is float around in one spot.
And I hate to say this, but I don't like oscars. I just gave mine to a guy with a 90 gallon, along with all the books and oscar food. I only had it for a few months, read about them, researched, and in fact it was the reason I got a 75 gallon tank. After owning one though, it was dull. It was boring, it pooped a lot ( I knew they were messy, but OMG!) and it limited the other fish I could keep.
Theory;
If oscars were rare, most of the same people who dislike them would suddenly want them. Disclaimer: I'm not pointing the finger at anyone here who hates O's. I'm not crazy about them myself and have no intention of owning another one.
transversely, If zebra plecos were as common as neon tetras, people wouldn't care one tenth as much about them as they do now.
This definetely applies. Some people can say they hate oscars all they want, but if they were rare like you said, then more people would be salivating over getting some.