[froglets]

You can buy tiny tablets to add to the water that prevent mosquito larva from developing but don’t harm anything else. I’ve used the Mosquito Killer larvicide in my patio pond for years and it works well. Garden centers sometimes have pond sections with water plants like hyacinth (very invasive), water lettuce, lily.

[WhatsTheBigIdea]

I'm doubtful of the "...but don't harm anything else" statement. Why do you believe this statement to be true?

[xsmasher]

It's true.

https://en.wikipedia.org/wiki/Bacillus_thuringiensis_israele...