C78 Tetrahymena

I took the key to open the door and entered the courtyard. When I entered, I saw that there were 1 m by 1 m large glass fish tanks on both sides of the courtyard.

Because it was too dark, he couldn't see what kind of fish were kept in the place. However, after walking further in, he was surprised to see that it was a double storey hall. From the 1st to the 2nd floor