Now found a dead platy in my tank seems to have some kind of sore on its head can anyone tell me what may of caused it and weather it could be something that could be harmful to the order tank mates
Looks like an internal head bleeding around the brain. If that's the case, it's probably just an individual issue that won't be harmful to other fish. But if I were you, I'd check out my water first if there's something going on or not. It won't hurt to check that out first.