Tadpoles generally feed from their tails until they become frogs and start taking tiny insects. What I may do to help them along is provide a variety of fish foods including algae wafers which they seem to like.
Also, try to do atleast a partial water change daily as it will help with development of the tadpoles into frogs.

I was told that tadpoles put out hormones into the water to prevent their 'littermates' from growing so that they mature faster... a survival instinct. My first attempt at raising tadpoles, I didn't know this and they took forever to become frogs. This time around i'm doing daily changes and they are morphing very quickly!

I'm no expert but I noticed you hadn't had any replies, just trying to help. I'm at my second attempt at raising several hundred tadpoles right now and it's a little challenging but fun too!

Take care, Joe
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Thanks and take care - Joe Rollo
'Tis not the stongest of the species that will eventually survive, nor the most intelligent, but the one most responsive to change' Charles Darwin