Hello, the umbilicus is prone to infection due to anatomic reasons - sometimes it s a closed space that may hold dirt, etc and favors bacterial growth. The fluid you ve seen needs to be drained and perhaps you should also take an antibiotic. I suggest a visits to a surgeon who will evaluate your umbilicus and perhaps through a minor incision will drain the fluid. This is not a very difficult situation unless you let it get worse. I hope you find my answer helpful! If you d like more information, you can contact me again. Kind Regards!