So, you have pet fish. You have already asked if they can recognize people, and now you are wondering if they can see in the dark. Well, you are in the right place to find out. Unfortunately, this is an extremely easy question to answer, no, they can’t.
However, instead of physically seeing, they do have pressure-sensitive areas on the sides of their body that can sense things near to them. That allows them to still swim and move around things without bumping into them at night. That has also raised the question of whether pet fish need dark, or if there is no need. Well, the short answer to that is yes, they also need dark. Just like humans, they need periods of light and dark.
So, next time you think about leaving the aquarium lights on, you should think about how you would feel having your lights on all of the time. You would get tired very quickly.