Which species of clingfish? You see the flat all most freshwater plec type that have been captive bred and are pretty easy, and the yellow stripe clingfish which are very difficult. I've only kept the later and it didn't go well. I found mine near impossible to feed and the only thing it would eat was cleaner shrimp eggs straight off the cleaner. I had to remove it due to this aggression. I've seen people have some success but wouldn't personally try another. On the other hand if I saw the flat place like species I'd jump at the chance to buy one.