May have to look closely to see them. I'd love a picture of the frog eggs to go with the post. As in KOI not getting enough of other nuitrients. Your opinion on the effectiveness etc. The video you refer to is over four years old.
Few lettuces have much nutritional value.
Romaine may be the most nutritious but even then - nominally. The video also does not cover potassium permanganate, anesthesia, nor does it demo any parasites. The new video actually covers all these things and is very up to date. You could, however, fill the fish up with lettuce and then they would be too full to take regular pellets. NOPE - not usually.