I bought 2 tadpoles a couple of days ago and i'm feeding them lettuce and fish pellets.
They're in a 4.5 gallon tank (17 litres) and have 1 oxygen plant in there.
But what they do alot of the time is swim around with their backs touching he surface,
Is it lack of oxygen of something else?
Are they actually gulping at the surface for air or are they just swimming in the top half of your tank? As long as they're not constantly gulping for air, they're probably fine. FYI unless your plant is huge, the amount of oxygen it produces is probably negligible. If your tadpoles are gasping for air, you can add a lot more plants, or better yet, a small filter to help keep the water clean and keep it circulating, adding oxygen.
How do tadpoles breathe?
Tadpoles breathe through gills. As they grow their gills start to shrink and become covered with flaps of skin and then their lung are formed. During this process the tadpoles swim closer to the surface of the water so that they can take in air. Once a tadpole develops its lungs it can then breathe air.
