I very much agree with you. Goldfish are so mistreated being seen as an easy child's toy/pet that you can stick in a tiny bowl.
But, I think if anything is abused and under appreciated, its got to be the common pleco. People most often do not buy them as an interesting fish to own, but in the false hope that they will make good vacuum cleaners for their 10 gallon tanks. They are an after thought even when bought. Then they get too big and people dump them, either to anyone who will take them or in a local body of water.
The giant common pleco I caught in Florida with a big net. The ballsy pleco sat and fought with me over his territory. (Yes, I have these pics up elsewhere).
I wanted so much to bring this guy home.