In my opinion, many types of carnivorous plants that live in water either fresh water or salt water.
In my place, there are so many plants that live in calm waters, one of the very many found are green algae, they also eat a small planton that lives side by side with it.
This type of algae in my place is widely found in citizen wells, the community also believes its existence can also be a benefit as a well water purifier.

image source : http://www.waternsw.com.au

Thank you Hive account@madiba has shared your interesting information. very helpful.