Rally Pro works for some things for some people. Part of any treatment depends on the extent of the disease. I assume OP that you're asking because you want to put it in your display tank with inverts.
To answer your specific question - I think it helps bacterial issues, flukes, and velvet.
Fin and tail rot are usually 'bacterial' - so it should help.
I assume 'clownfish disease' means brooklynella. My answer would be not as likely as the others.
I said 'helps' because I think there are better treatments for each of the ailments you mentioned - but there are many reasons to use Rally Pro. JMHO. It depends - do you want to treat in a display - with inverts, etc.
PS - I do not think that it works well for Cryptocaryon