Trout can see at night but only black and white and vision is reduced. They adjust to the light level. The deeper the water the less light and worse they can see.
Most fish have a lateral line that runs down the side of body which house Neuromasts. For the most basic description the fish can sense what is around them through these neuromasts. Most fish in their natural settings do not receive as much light as we give them in aquariums, the water depths are deep and dark and the fish has to have a way to find food, sheltering areas etc. Deep sea fish have eyes suited to dark environment.
Water rapidly removes all wavelengths of light other than blue, and most of them have eyes which are adapted to see optimally in dim, blue wavelengths of light.
Deep-sea fish live in total darkness, and often emit blue bioluminescence to lure in prey, communicate with each other and illuminate their surroundings. Some deep-sea fish have the ability to emit and detect red bioluminescence, allowing them to see other fish that may be unable to see them.
Fish have no eyelids so they cannot close their eyes but they do sleep. Some fish sleep. If you shine a flashlight into your aquarium late at night, after the aquarium and room lights have been off you will see most of your fish just hovering, often not far above the bottom.