I just bought my first camera that wasn't under $50. A Canon Powershot sx40 hs. I've never really been into photography, then I started seeing some of these photos and have been interested. This is a digital with a fixed lens, but a pretty decent zoom to it and it does have some features you're mentioning like aperture and macro. I haven't even scratched the surface yet. I'm wondering can this camera act similar to a slr? I mainly got it instead of the slr because it also shoots 1080p video as well.
I don't know much about that camera.
Does it have an eyepiece/viewfinder or just an LCD?
When you take a picture do you hear a clicky noise?
A lot of cameras have a speaker that plays a simulated SLR mirror flap noise, but you can typically tell the difference.
Eitherway, it should work more than well enough for Aquarium Photography except you won't ever be able to change lenses - which is good if you had no intention of buying any.