I have read recently - that dinoflagellates 'kill corals and fish' - I noticed (after months with none) - and after a failed alkalinity doser that some parts of a couple corals died off - On those dead places - some dinoflagellates have started growing. They are not on any other rock, etc - except where the coral died. (well - maybe a couple spots on rocks) - but very few. See the poll and lets discuss? Note - I realize there are many kinds of dinoflagellates - I'm talking about the common brown stringy masses that everyone hates. I mean zooxanthellae are dinoflagellates after all... PS - I'm sure there are cases where dinoflagellates can release toxins - I'm talking usually/ in general