Pet Shop of Horrors: Collector's Edition manga volume 3 features story and art by Matsuri Akino.

When a reclusive systems engineer is found dead in his apartment, Leon heads to the pet shop to ask Count D for help with the victim's collection of expensive tropical fish. However, it soon becomes clear that the count can do more than just care for the fish - he can talk to them too! Can Leon set aside his disbelief long enough to solve the murder with D's help?