Cardinals in an urchin is normal, wrasse in a RBTA well that could be trouble.
The rule %99 of the time is that clowns host nems nothing else. RBTA are not strong stingers and if the fish can develop a resistance to the stings, it will be fine. There was an article a bit ago about an angel hosting a carpet, so it happens occasionally. In the wild people have found cardinals hosting nems as well.
Awesome job!!!
My clowns host my orange crush Acan colony they actually lay flat on it. First time I saw it I thought they were dead....Interesting. In my tank the clowns host the nem, the hammer, pagoda, and some palays. So far the wrasse is following. Brushing the nem very lightly do I guess it's building up it's immunity
Twisteds 40 breeder