Oh dear. Tadpoles are no more. Several of them hatched out at school, but then the tank started to get mucky. And scummy. And stinky.
I called in school wildlife expert Joseph, aged 9. 'They need pond weed,' he pronounced, a slight frown on his face as he stared at the tank. 'I'll bring some tomorrow.' He did. Things didn't improve.
I called him in again. 'Two thirds of the water needs changing,' he asserted, the frown now deeper. He and a friend duly did this, using water from the school pond. Then we noticed the leech.
It wasn't until I had successfully trapped the leech, releasing it back into the pond, that I realised how truly smelly the water was. I had to wash my hands several times with soap to get rid of the smell.
So we emptied the contents of the tank back into the pond. The leech was happy.
No more tadpoles.
However, I did notice more frogspawn in our pond at home...