You might have noticed in recent videos that I don't have my yellow tang any more. Sadly it died. The cause was marine flukes.
Flukes are a parasite that can quickly multiply and kill all your fish.
Flukes are far easier to treat than marine ich, or velvet.
Things to look out for are
1: lifeless looking fish.
2 :Scratching on rocks.
3: Heavy breathing.
4: lack of appetite.
5: cloudy eyes.
6 Hiding under over hanging rocks.
7: white/translucent tiny slug like creatures on the body.