I think I caused it by not rinsing him out properly after bathing him a few weeks back... but as he's in quarantine (just moved barns) for the next two weeks I won't be able to bathe him again with anything anti-fungal, medicated or anything that requires being rinsed out until the first of May.
Is there anything I can do in the meantime to help manage the flakes. There rather big (some flakes as much as two-three millimetres across) and kinda gross - they almost remind me of rainrot - can a horse get rainrot in his tail?
What kind of solutions are out there for dandruff that don't require immediately being rinsed out? I've read about listerine.... does that ACTUALLY work?