Suihelibe!

First-year junior high school student Tetsu is alone, minding his own business, when a small flying saucer crashes into the classroom. The pilot happens to be a cute space girl named Lan, who looks surprisingly human despite her alien heritage. When she realizes her life forms escaped during the crash, Lan knows she can't recover all of them on her own. So she enrolls in school and joins Tetsu in the otherwise memberless and soon-to-be-defunct biology club. And just like that, THE ALIEN ANIMAL HUNT IS ON! (^___^) [quoted verbatim from the blurb of Volume 1]