Tadpole failure

I feeling so sad now, left with four tadpoles after so many casualties. Really have no idea what happened to this batch of tadpoles why the survival rate is so low. I guessed water, lavender tea, glucose and Pu Er tea all not that good after all ba. I will be expecting more deaths to come, sigh. Last time I tried Spirulina drink solution on them, worked quite well lei, 2 out of 9 survived to froglets, would be 3 if counted in one which jumped out and got killed by my naughty cat. However, the drink concentrate ran out and quite expensive to get another bottle. That time happened to have. This time over 30 plus tadpoles left only 4, sad.


This photo was of the past year tadpoles, can't remember which year.
The water is clear, not the Spirulina solution cause they were quite grown up so I thought there wasn't a need to.

The Spirulina solution was pale green in colour.