That's a defect. I had 1-2 new filters do that but most haven't. The fishy smell is what you get when the filtering system starts to break down. Apparently not

That's a defect. I had 1-2 new filters do that but most haven't. The fishy smell is what you get when the filtering system starts to break down. Apparently not harmful but means it is time to switch. From comments elsewhere it seems there are mixed reports about microplastics removal from Zero water (or other types) so now I'm unsure what to recommend.