So to be more specific here your orange angler has ich.
Where did you aquire this fish from?
How long have you had it?
What have you been feeding it?
What are you water test results?
What has it been eating if you have not had it for that long?
What size QT is it in?
These fish are very hardy and it's really hard for them to get ich unless something is wrong. I have seen whole tank outbreaks and all the fish dieing but a few including anglers and toadfish. As far as my two earlier questions you didn't answer either of them, telling the me water is okay means nothing. That kind of points to the fact that you have no idea or are to lazy to just test the water and type the results down on here. If you don't have a test kit, you should get one. I also asked about the diet because bad diet leads to any fish getting ich easier. So when you say 6 fish in the tank, what is that suppose to mean? 6 damsels? 6 gold fish? 6 frozen smelt? Or are you just not feeding it?
Seems like your dodging questions that I need answered to help you.