One of my neons sadly passed today. He was fine this morning, eating with the rest and schooling then I went to get changed at about 4.30 (last looked in on them at 11) and I noticed something in the filter intake (which isn't very strong). The poor guy was in there. Ky had a go at home when I turned the filter off to get him out but when I inspected his body there were no wounds and his tail was fine. He still had plenty of colour so it couldn't have happened long ago. I'm worried about neon tetra disease now. I know it's common in shop baught neons, what are the symptoms and does it come on this quickly?
RIP little guy. Sorry I couldn't do more for you.