i dont totally agree with this if its "fish to avoid"....ive had and still have tangs with my reef. ive kole tangs,powder brown,regal,yellows,scopas tangs and ive had 2 different species foxfaces and currently house a coral beauty angel which ive had for 2 years.
and everyone i know has some form of tang in their reef tanks.
granted angels are a RISK in a reef but i and a friend have had no issues out of either of our coral beatuies. neither foxface i had gave any issues and one is now housed in a friends 180g reef with a scopas tang, sailfin tang and a regal and NO ISSUES....
alot of fish ive noticed people say dont use are a CHOICE....maybe because theyve had a bad experience or heard some say they have....
ive been doing this 3 years and NEVER had a tang munch on anything it wasnt supposed to and ive ALWAYS had zoa gardens....
any fish that says WITH CAUTION on its reef compatibly is a risk to house with certain corals. and ALOT of angels are NOT reef safe.
just do your research on fish BEFORE you buy them and ask around for someone that has had or may have a perticular fish your interested in and get some first hand info.