1/4 white larvae with one black end in my koi pond bottom drains.

[harriduck]

I have had a 4k gallon koi pond for 40 years. I changed my pond liner from 80 mil EDPM to butyl rubber last December. My pond has bottom drains. The pond water gravity flows underground to a 6’ diameter x 6’ deep settlement tank where the water slowly circulates clockwise so debris does out before the water is picked up by 4k pump that sends the water to my bead filter tank, then back to the pond. The settlement tank surface level is the same as my pond water surface. As water is pumped from the tank to the filter, pond water is pulled back through my bottom drains in a loop. This time of year, the bottom drains become clogged with leaves, which I have to clean out to keep the system flowing smoothly. For the very first time, the leaf detritus has lots of 1/4” white larvae with one black end. Photo attached.

 

[j.w]

@harriduck

 

[permaculturebob]

for a positive id a better closeup would be helpful.
from the description, it sounds like an anaerobic situation, is that the case? are they growing under water?

 

[GBBUDD]

i don't see larve of any kind as a bad thing but it is a sign theres enough food to feed them and for them to continue to breed. Is it that there's uneaten food making its way to them ? be it due to over feeding and it not being digested fully or pelets making its way to them. Or is it a natural thing like leaves decaying " a major food source in the wild. as they break down many eat them or as fungus starts to devolope they may dine on that. answer what they are feeding on and youll solve your issue. Imo it is a sign the pond is healthy, as they are higher life forms. This is also the benifit of the eco pond style as no one does it better than mother nature.

 

[Rick42wood]

i don't see larve of any kind as a bad thing but it is a sign theres enough food to feed them and for them to continue to breed. Is it that there's uneaten food making its way to them ? be it due to over feeding and it not being digested fully or pelets making its way to them. Or is it a natural thing like leaves decaying " a major food source in the wild. as they break down many eat them or as fungus starts to devolope they may dine on that. answer what they are feeding on and youll solve your issue. Imo it is a sign the pond is healthy, as they are higher life forms. This is also the benifit of the eco pond style as no one does it better than mother nature.

Take a couple out and keep them in a jar of the same water and debris and see what they hatch into. In the meantime if they are also in the pond the fish will love them.