Weird algae

[fishymom]

Hello fellow fishy folks,
I have a friend who has this koi pond. He's asked me about the weird algae at the bottom of his pond. I think it's algae. If anyone can help me to identify it, I can let him know so he can take care of it. Thanks.

 

[GBBUDD]

looks like what is referred to as bio film. It is algae and when short fibrous coatings its a sign of a healthy eco system

 

[JRS]

I am looking at the round growths? Reminded me of something in a saltwater tank. Perhaps a freshwater sponge, if so benign like the biofilm as mentioned. Perhaps Ephydatia muelleri: https://www.ualberta.ca/science/news/2020/july/freshwater-sponges.html

 

[fishymom]

I will pass off the information to my friend. Thank you all for your input.

 

[sissy]

clean liners are not healthy liners .