This morning, I get my camera out immediately. I am on a mission. As soon as we get in sight of the reef, our group disperses to look around. We’ve swum into a semicircle of coral, and Vanessa hangs out at the opening of the structure so she can keep eyes on all of us at the same time. Miguel is swimming around, pointing out interesting fish. I beeline for the staghorn coral, where butterfly wrasse like to hang out.

The reef is just as breathtaking today as it was yesterday. Coral doesn’t grow uniformly, it builds and layers on each other, creating nooks and crannies teeming with life. Everywhere I look I see a different species of fish. Some fish have huge, flapping dorsal fins, some have spots, or stripes, or patches just above their eyes. I’m starting to feel like underwater is technicolour, and every-thing else is black and white. As I kick forward slowly, the coral fissures below me and I spot the dark green ribbon of an eel as it streaks through the rocky crevice.

I drift a couple of feet further, until I’m hovering over a flat bed of coral. Staghorn coral make up about 25 per cent of the Great Barrier Reef’s ground cover. They come in many sizes, shapes and colours. All of them branch out, some resemble elk antlers, some are small and look like miniature forests, and some branch high into the sea, swaying in the current, and look more like pointy sticks.

I hover over a bright blue structure of staghorn branching up towards the surface. There are hundreds of fish darting around, most of which swim away as I get closer, but after I pause, doing my best to hover without kicking too much, the fish return.

I start snapping pictures as fast as I can. I don’t see a butterfly wrasse, but I’m hoping I can comb through the pictures later and find one. It’s hard to focus on one fish at a time when they are all moving. I bet Millie could do it, I think. As soon as she crosses my mind, my thoughts snowball.

Why did I think I could do this? What if I don’t find the fish? Will it be because it doesn’t exist or because I’m bad at this? Will this be the last adventurous thing I ever do?

My lapse in confidence causes me to lose focus and I almost kick the coral beneath me. Frightened, I swim away from the reef, backpedalling towards Vanessa. From there, I watch as the divers continue to explore. I feel defeated, floating in the ether, untethered, like I could drift off into the ocean, letting the current carry me further out to sea.