Hello Fishlore, One of our female platys has had this white spot on her head for about a month now and we didn't think much of it initially as it didn't seem to affect her, but lately it seems to be getting bigger and she's behaving a bit differently. Her dorsal fin is always down, and she spends most of her time under the filter stream. I'm wondering if it's not a rash of some sort that is irritating her, and the water stream is providing some relief from that? Does this look familiar to anyone here? It seems very different from Ich as it's not in her fins and it's not little spots, rather just one large white patch. Any help much appreciated.