Tadpoles deal one damage and have one hit point. They simply swim around, approaching the player if they get too close.
When out of the water, Tadpoles will helplessly flounder around looking for water.
Tadpoles aren't much of a threat unless the player is rushing through, as the most hazardous place to find a Tadpole is in a large lake above a pit of Spikes. Even when the player is carrying Hou Yi's Bow, they may simply set it down before the lake and defeat it with their whip, making them a trivial enemy.