Blue Frogs in deep dark

Blue frogs were first shown in concept art and they were scrapped but i think they should bring it back. just like blue axolotl very rare but not naturally spawning. if you breed frogs in the deep dark and there is water nearby there is a rare chance that the tadpoles will turn into blue frogs or instead just become the frog on the basis on the biome above the deep dark. wardens should not be hostile to them but follows them like its his pet and that could be a distraction to escape deep dark. I hope for your respone