Mina is quite a slow Peophin. She and her friends, Rhys and Toby, went to the Rock Pool after Mina saved up enough Neopoints for a Petpet. However, because Mina was so slow, the Rock Pool was sold out. Thankfully, on the way out she saw a lone Peo, and adopted it.
From the picture with the story, it appears Mina may be a yellow Peophin. She appeared in issue #8.