If you created the page /wiki:penguin and you realize that it should be moved and/or renamed, for example to /en:penguin, then here is the procedure to follow:
In case of error, one can easily retrieve a page destroyed via the history. It is also easy to move a page. So do not be afraid when making a mistake!
If you need to move a lot of pages in one go(or if the page to move is bound by many links), the administrators have a tool to do this all at ones(automatically), so be sure to contact them.