So in the last episode of Smarter Every Day we revealed that fish eat by sucking in the water by opening up their mouth

and then once they do that they allow the water to exit back behind the operculum by opening up their gill flaps, it's really cool.

But the problem was we only captured the footage above water.

So Dr Seymour and Richard Fitzpatrick at James Cook University have gone back and they made a rig so they could do it underwater.

So let's go check it out.

- So we're gonna do the barramundi high speed feeding sequence again for you but this time from under water.

What we've done is we've modified this camera housing,

we've put the Phantom camera inside there.

Jamie's gonna use his stick with a prawn but no hooks, so we're not damaging the fish at all,

and we shall see how they look at high speed from under water.

Yep, little bit closer to you.

Ooh! Got it!

- Looked good.

- So let's have a look.

(Destin) Alright here we go.

Watch the water flow through the mouth and out the gills.

But why doesn't the water flow in through the gills?

If you watch closely it's because the flap overlaps and it slams shut like a check valve

only allowing flow in one direction.

(Jamie) That is awesome!

- OK we hope you like that one Destin.

That demonstrates everything, but under water.

Bye from Australia. Ciao!

- See ya buddy!

OK the next thing we're gonna look at is the fact that fish can throw their lips forward.

Now this helps them close the gap with their prey.

There's two more clips that Richard sent to us that we're gonna look at.

The first one is the stone fish, which you know is the most venomous fish in the world.

It closes its gap really really fast with its lips, it's amazing.

The second one is called the slingjaw wrasse.

Now this one is just unreal.

It's like a mechanical hinge structure, I'll let you see it.

But everything is in slow motion. Check it out.

So the stonefish just chills out looking like, well, a stone, until the prey gets within its strike radius.

Then this happens.

This is a slingjaw wrasse.

Prepare your brain for what you're about to see.

Yeah.

That's crazy.

Let's watch it again from the side, and you can see if you look close the shadow of that little fish as it zips up through the sling jaw.

OK I hope you enjoyed learning how fish eat along with me.

Thank you to Richard Fitzpatrick and Jamie Seymour for giving us this footage.

If you want to see more awesome stuff that they do on the Great Barrier Reef, and their Phantom footage under water, it's amazing,

go check out biopixel. They have stock footage that they make,

just go look at it, it's amazing stuff.

Also if you want to check out more stuff like this fishing trip you can follow me on @SmarterEveryDay at Instagram.

I've been taking pictures of water striders and stuff like that.

Anyway I'm Destin, I hope we earned your subscription today. You're getting Smarter Every Day.

Have a good one, and go check out biopixel.

Take it easy.