We got a new light fixture for our aquarium. The old one fizzled out in stages. Sometimes it'd work, then a week would go by when it didn't work, then it'd work again a couple days, like that. Finally, as the end of these things usually goes, it didn't work period.
So we improvised with a stand up light fixture, beaming light in from the side. This worked well enough to keep the fish from becoming blind mutants but not really well enough to enjoy looking at the fish. Too many weird shadows. If one fish got too close to it everyone else was in the shadows. Plus you the viewer are staring into that weird light from the side.
Now we have a brand new fixture, beaming from above, and it's a vast improvement. It brings out the colors of the fish in a nice way and makes it enjoyable looking again. I was looking in and the place seems to be crawling with life. Lots of activity is going on in there.