My brother builds aquariums for a living, to keep aquatic plants or animals in to be displayed or as pets.
That's pretty cool! I would love to have an aquarium 
Robert Warington actually created the idea for aquariums back in 1850. He explained that plants added to the water would give off oxygen to support the fish.
In 1850? Wow! That's a long time ago. I didn't know you have to have plants in aquarium. 
You don't have to, but it helps with oxygen. Especially if there are large numbers of fish or aquatic animals.
Oh, I see! That's very good to know!
You can also go to public aquariums if you like fish, they have them in many cities.