Hi, I am new here and I don't know very much about tadpoles at all. We have been given some tadpoles from a friends pond, there seems to be two very different tadpoles in there. The larger ones are almost green, I can almost see the frog they are going to grow into (common for the area, what ever it's name is, green with gold). The other single lonely tadpole is tiny, less than 1/5 the size of the others and seems very black. It seems to behave differently also, hiding more, and when I changed their water it swam the opposite way to the other tadpoles (more natural instinct by the looks). Can anyone tell me what this little guy might be called? Is he just a younger version of the others or a different species? I know he is not a native as they don't have tadpoles.