Originally Posted by Bubble_B0y
Labyrinth fish (bettas, gouramis) all possess a respiratory organ that allows them to breathe at the surface of the water.
Does this mean you can drown and suffocate your fish, if they cannot reach the top of the tank?
To the best of my knowledge...
They have this breathing system because in the wild, they live in river systems that can dry up and get shallow, so it a precaution against dying in small pools. This organ has become a necessity for them to get the oxygen they need. So, yes, they could suffocate if they cannot get to the top.