Everyday, about 20 times, my clown knife for some reason comes out of his house and heads straight for the surface. His head will breach and then he will go right back down and in his house again. it looks like he is going up for air, he coughs air bubbles on his way back down. Why does he do this?
My knife wants air?
- Thread starter graham
- Start date
Clown knife fish (and many other types of fish) have evolved an alternate method of breathing due to drops in O2 levels in the waters they come from (drought conditions). Clown knife fish have evolved an adapted swim bladder that is lined with a highly vascular epithelial layer that functions as a lung. It is a continuous air breather. That means that even in conditions where O2 levels are sufficient, the knife still must replenish the swim bladder's air on a regular basis. In clown knife fish this is about every 6 to 8 minutes.
It's nothing to worry about. Like Oddball said, they breathe air from the surface when oxygen levels are low.