The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
In Chinese Medicine hydrothorax can be treated by one herbs that we have on record. Here is the list below.
Genkwa flower might help with hydrothorax
Why might Genkwa Flower (Yan Hua) help with hydrothorax?
Because it is a herb specifically indicated to treat hydrothorax as can be seen on Genkwa Flower's page.
Genkwa Flowers is a Warm herb that tastes Bitter and Pungent. It targets the Kidney, the Large intestine and the Lung.
Its main actions are: Relieves chronic congestion of Fluids in the chest and stops cough. Drains congested Fluids through the urine and the stool. Expels parasites.