We've been living in the same home for over 6 years. It's a normal, modern home & we keep it clean. Maybe 6 months ago, this strange smell appeared in my daughter's bedroom. It's a combination of musk, fish & just plain stink. Sometimes it only lasts for a few minutes, sometimes hours, sometimes days. Then, it goes away without a trace. It may stay away for days or even a week. But, then it comes back. It's strong.

We've sniffed everything in the room, including my daughter & can't identify a particular item or even an area of the room where it seems to originate.

Any ideas?