text: Hi! Well, it _is_ normal for tadpoles to have high mortality rates. After all, only a few of the hundreds of eggs will finally grow into adult frogs or toads. Some are eaten by birds, some are parasitized or just die because they were not well developed.\nBut if it is a large enough pond, at least some tadpoles will grow normally. And remember what I said about the water (I left comments in the other question): if it is not at least partly renewed, the concentration of ammonia will rise too much.\n\nOh, and another thing. When they first hatch, the tadpoles still have a bit of yolk from the egg and do not feed; only after a few days they develop their horny beaks and start scraping the algae. So it might be that now they're staying closer to the bottom surface, and that's why they're less visible. \nI'm including a link to a site that shows the developmental stages for most tadpoles. The stages are numbered from 1 to 46, but the time it takes for the entire process to be completed depends on the species and also on environmental conditions: \nhttp://www.trentu.ca/biology/tadpole/Webstage2.htm\n\nTry to catch a few and see which stage they're at :-)\n-------------\nPS I've just read the last comment. What exactly is the "clarifier"? Tadpoles are very sensitive to chemicals, please don't add anything foreign to the water!