The answer is yes. Fish can see air, but it’s not something that they need to survive. As ichthyologists will tell you, fish have a variety of ways to sense their environment and find food without the use of sight. In fact, more than half of all fish species are blind in some form or another.
The ocean is full of microorganisms that fish can feed on, and they’ll do so by either filtering the water for plankton or waiting near the surface for small prey to float down from the top. The catch might be invisible to them, but there are plenty of other signs like smell or sound clues. Some species rely more heavily on their senses than others though; skates and rays have a hard time finding food without eyesight.
There’s one more thing about fish vision you should know: it doesn’t work well in low-light conditions. It makes sense when you think about how often these animals come up close with things they see at night. Manta rays use electroreception instead which helps compensate for this lack.
