Tadpole Raising Questions

[RandomStranger]

Ok, so from google and personal knowledge, it is my understanding that the key to raising tadpoles is to keep their water from getting murky and giving them lettuce every once in awhile (pretty much everything I found says tadpoles should be fed lettuce). Just wondering if there is anything I'm missing. Seems pretty straight forward and low maintenance but I don't just want them to survive, I want them to thrive. So if there are other things I can put in the water for food (if they do better on diverse diet?) let me know. I put a small piece of a dead fish I found near where I found them... they seem to actually be eating it every once in awhile. I thought they were just herbivores but I tried it anyway.