Fun fact about myself: I build aquariums for a living. 
Is that hard?
Well, the concept is simple-plants, water, and a container, but larger ones can be difficult
What is that thing aquariums have that filters out the bad bacteria and germs? The motor thing from Finding Nemo.
I like to build my aquariums without a filter, but rather, I like to place enough plants in the aquariuam so they produce enough oxygen to sustain the tiny ecosystem.
That is so smart. It like an underwater rain forest!
The craze of keeping fish started way back in Early Victorian England