This was a windy day. The sky was very blue; some clouds were floating. I was riding my bike to school. But I accidentally went into a shopping mall.
There was no one in the shoppingmall. All the stores were closed. I was wandering around.
I’m on the second floor of the shopping mall. There were a big stair and a long swirling slide for me to get down. Since I was riding a bike, I chose the slide.
It was so weird that there’s only one floor, but it took me a long time to go down. While getting down, the light was getting dimmer. More reflections of the blue water appeared on the walls that surrounded me. I stopped. There was a sign of “aquarium” above my head.
There were many people inside the aquarium, it was so weird that the mall was very quiet, but the aquarium was filled with people. I wanted to get out, so I got inside and tried to find the exit. However, there were less people, and the place was quieter as I explored deeper, until I stopped at a gorgeous place with no people around.

I saw many different tropical fish in different colors and size behind the glass, most were neon yellow with black and white stripes, some were orange, some were dark blue with yellow tail, some were black. They were dancing around the coral reefs. I touched the glass, then I got inside the glass, with the fish around me, and I couldn’t get out. My bike was still outside. I looked around, then I saw a huge fish, this fish was the most unique fish among the rests, it was enormous, and it has all color of rainbow, red, orange, yellow, green, blue, indigo, violet shines under the cyan water. I believe this was the fish king in this fish kingdom. So, I rode on it, it started to rise to the top like an elevator.
In the sky there are many fish that are flying, like us. There was a shining mirror floating in the sky. When I got beside it, it suddenly flipped down, I fell inside.
I was sitting on a tree right now. It was the big tree beside our school. I walked into the school.
An interesting idea but a little confusing where you make jumps. I suppose the overall feeling you are trying to evoke is ‘weird’ and you certainly achieve that! Note that there’s a confusing tense slip at the start of your third paragraph.