I just remembered talking to someone in my class about all those tik toks on H2O (the ones where they talk in such a messed up Australian accent sjdhjs) and she would basically go "nO, not H2O it's m a k o m e r m a i d s. H2O copied mako." So, I searched up mako mermaids and then I searched up H2O, mako mermaids came out in 2013 from what I've seen and H2O in 2005 AND it literally says spinoffs and the first one is mako mermaids. :)