Call Me Princess and Aquarium by Tomoko Taniguchi

Both published by CPM Manga. All ages. Please note that both of these manga are in standard graphic novel size (about 26 cm tall) rather than standard manga size.

Call Me Princess blurb:

"This is the story of Mako, a teenager in her first year of high school, who finds herself torn between her feelings for her first love, Yo, and her attraction to the newly arrived bad boy, Ryu."

Aquarium blurb:

"Naoka has been turned down by the prestigious high school she wanted to attend, and in her disappointment she turns to the aquarium, where the glittering water and flashing bodies of the ocean creatures allow her to forget for a time the difficulties of life. In this moving coming-of-age story by Tomoko Taniguchi ... she learns to accept the joys and beauties of love and to treasure her family and her friends."

(Additional note: Aquarium is actually a short story, there are two others in the same volume, "The Flying Stewardess" and "The Heart is Your Kingdom". )