Killifish

The Killifish (メダカ, Medaka) is a tiny fish found in the holding pond between April and August at any time of the day.

In
As with all fish, the Killifish may be given to Blathers as an addition to the museum's aquarium.

The Killifish can be found in the first aquarium tank after being donated.

In
Upon donating to the Museum in, Blathers will say the following:

It can be found in the left tube tank.

In
Upon donation to the museum, the information board in front of the tank which houses the Killifish reads the following:

In
Once donated to the museum, the Killifish can be found in the small fish tank in the first exhibit room with the Goldfish and the Pop-Eyed Goldfish.

Real-world information
It is unclear what sort of killifish appears in the. Judging by the size estimated within the built-in encyclopedia and the Japanese name, it could be a Japanese rice fish. However, all killifish have common traits, noticeably, their translucent skin which has made them an interest in biology due to the visibility of their digestive system. They are a harmless, common, aquarium fish.