Fish Tanks

I've had a question on my mind lately, namely, to what degree do fish understand their environment? This came to mind sometime early this week when my room-mate Shane and I drove over to Best Buy, I needed to buy a charger cord for my ipod, and he was looking to replace a wireless router with something that actually worked. Without too much trouble or use of time we were able to find what we were looking in Best Buy. However, we realized that we were a bit bored, and went into the adjacent PetCo.

The PetCo there is another big box store, a part of the same strip mall as the Best Buy. These stores run along 494, a highway in the suburbs of the Twin Cities. The PetCo was an interesting place, and I wanted to look at various animals. The animals had to wait, for I had more pressing concerns. I quickly walked to the bathroom, pausing momentarily to marvel at a Wienie dog who waddled beside his middle aged human owners. This admiration was my downfall, as it distracted me from the matter at hand, and allowed me to step in a pile of fresh dog droppings.
I didn't notice at first, so I probably tracked the shit for about three meters before I noticed and began hobbling to the bathroom. My hobbling was good enough to avoid spreading shit on any other surfaces, which is a very good thing. I did my business, cleaned the offal from my shoe and went out.

It was at that point that I began looking at animals. First birds, then reptiles and amphibians, followed closely by fish. I gave the fish only a cursory glance at first, noticing that Shane was nowhere to be found. So, I walked around looking for him, and eventually discovered him looking at various cat toys. The idea was to buy a toy for our friends' new cat, Lyon. So, we browsed the cat toys for a few minutes, and then gave up to look at fish.
We looked over a large number of fish, of particular interest was a huge goldfish that stared blankly out the tank, zebrafish, and a sort of spooky, translucent fish whose tiny internal organs and skeleton were easily visible to the naked eye. I mistakenly thought that a large clear area around the tail was just empty space before remembering that the bodies of living things do not have empty compartments. I guess the muscle was clear.

Looking at the blank eyes of these fish, I wondered if they have good enough eyesite to look back and have even the vaguest idea of what is happening. I also wonder if they understand that their living situation is unnatural, and strange. I imagine that if I were smart and perceptive enough, living in their position would be stressful. Picture a small enclosure big enough to run a few laps around for exercise, with clear walls that lead out into an alien expanse. The giants lumbering around in that space would certainly seem like a threat, if they even seemed to be alive.
There must be some fish that are intelligent enough to get what is happening to them.