My aquarium

One day, I kept watching at my aquarium which my friend gave me two moths ago. It was a coincidence, her mother didn’t allow her to feed any kinds of animal at home and I wanted to feed fishes since I moved into my own room. Therefore, she gave me for free. There were too many to count and they swang very fast. Especially, three small shrimps in it, their bodies were very clear that I could look through them to the other side of the aquarium. I wonder how their life likes in the aquarium because they stay in a limited place for their whole life. Are they happy or not? What do they do in it? All silly questions came to me while looking at the aquarium.