The Ultimate Oxygen Vacuum
Imagine trying to breathe through a tiny straw while running a marathon in a swimming pool. That's what life is like for a fish! Water is "heavy" and has almost no oxygen compared to the air we breathe. To stay alive, fish have evolved into the world's most efficient oxygen-vacuuming machines. Their gills are so amazing that they can suck out nearly all the oxygen from the water passing through them. If you unfolded a tuna's gills, they would be ten times bigger than the fish's entire body! It's like having lungs the size of a whole living room stuffed inside your neck. Learn more!
Wee Ones
A fish has 2 eyes, 1 mouth, and 2 sets of gills. Can you "see" how many body parts that is in your mind without counting one by one?
Little Kids
To get enough oxygen, a fish "breathes" 80 times every minute. If a fish takes 10 breaths every few seconds, how many times do we have to count by 10 to reach 80? Let's skip count by 10s to find out!
Big Kids
A tiny piece of a fish's gill (called a lamella) is a rectangle that is 2 millimetres long and 1 millimetre wide. What is the area of this tiny piece in square millimetres? If the fish has 100 of these tiny pieces in a row, what is their total area?
The Sky's the Limit
Fish are super-efficient! They can extract 80 percent of the oxygen from every gulp of water. If a gulp of water contains 10 milligrams of oxygen, how many milligrams does the fish actually suck into its blood?