Sure looks like it to me but some of the guys on here will know for sure. Last year my newly redug pond had a little but not bad. This year it exploded faster than I realized it could. I had floating mats of the stuff covering half the pond. Sprayed half the pond with Cutrine Plus last Friday and it turned it brown in a day and it is sinking now. Going to spray the other half of the pond next nice day. Good luck.