Animals
I have never picked a destination and hoped. I pick an animal — a thresher shark, a mandarinfish, a pygmy seahorse the size of a fingernail — then work out where it lives, when it shows up and how deep, and build the trip around that. This index is that habit written down.
So it starts with the animal rather than the country. Each page gives the destinations worth going to, the season, the depth to plan for, whether it means a night dive — and an honest read on your odds, because this is wild animals and nobody can promise you one.
This site is the notebook behind Tortuba — a dive log and fish guide for iPhone and iPad. Free, no account, works with no signal.
What the rarity tiers mean
How often you actually meet the animal on a typical dive within its range. It rates the species, not the destination — so a Unicorn can still be a near-sure thing at the one site built around it, and each animal page says which sites those are. Nothing here is a promise: these are wild animals.
- Crowd Pleaser ~4 in 5 dives — Almost guaranteed
- Usual Suspect ~1 in 3 dives — Frequent
- Shy ~1 in 10 dives — Regular, but it has to want to be seen
- Collector's Item ~1 in 25 dives — Rare enough to plan the trip around
- Unicorn ~1 in 100 dives — Call everyone if you see it

Manta Rays
Mobula alfredi & Mobula birostris
A gentle, plankton-feeding giant with a wingspan of up to 7 meters that glides over reef cleaning stations and feeding grounds.
6 destinations →

Whale Sharks
Rhincodon typus
The biggest fish in the sea — a slow, plankton-feeding shark that can reach 12 meters yet is completely harmless to swimmers.
6 destinations →

Hammerhead Sharks
Family Sphyrnidae
The hammerhead family — a handful of species built around the cephalofoil, that flattened hammer of a head. The one divers cross oceans for is the scalloped, which gathers in schools of hundreds.
1 destination →

Mola Mola
Mola alexandrini
The heaviest bony fish in the ocean, which rises from deep water to Bali's cleaning stations for a few months each year.
1 destination →

Thresher Sharks
Alopias pelagicus (pelagic thresher)
A slender deep-water shark with a whip-like tail as long as its body, which it cracks overhead to stun schooling fish — and which visits shallow cleaning stations at dawn off Malapascua.
1 destination →

Sea Turtles
Chelonia mydas (green turtle) & Eretmochelys imbricata (hawksbill)
The green sea turtle — honu in Hawaii — is the reef's most beloved reptile, and the only sea turtle that hauls out to bask on land almost daily.
1 destination →

Wobbegongs
Family Orectolobidae
The wobbegongs — flat, bearded carpet sharks that lie still on the reef and let their camouflage do the work. The showpiece is the tasselled wobbegong of Raja Ampat.
1 destination →

Blacktip Reef Sharks
Carcharhinus melanopterus
The small, black-and-white-finned shark of the reef flat — the one whose dorsal cuts the surface of a lagoon in ankle-deep water.
3 destinations →

Basking Sharks
Cetorhinus maximus
The second-largest fish in the sea, and a surface-feeding plankton eater you meet by snorkel rather than on scuba.
1 destination →

Grey Reef Sharks
Carcharhinus amblyrhynchos
The classic Indo-Pacific channel shark — a sleek grey torpedo with a black-edged tail that holds station in moving water.
3 destinations →

Leopard Sharks
Stegostoma tigrinum
A spotted, bottom-resting carpet shark with a tail nearly as long as its body — asleep on the sand by day, hunting shellfish by night.
3 destinations →

Pelagic Thresher Sharks
Alopias pelagicus
The only shark that hunts by whipping its tail over its own head — and the one thresher a diver can actually plan to meet.
2 destinations →

Great Hammerheads
Sphyrna mokarran
The largest hammerhead — a solitary ray-hunter with a scythe-like dorsal fin, and one of the hardest big sharks in the world to find on a dive.
1 destination →

Scalloped Hammerheads
Sphyrna lewini
The schooling hammerhead — the one that gathers by the hundred over the seamounts at Darwin and Wolf, and off Yonaguni in a cold Okinawan winter.
1 destination →

Tasselled Wobbegongs
Eucrossorhinus dasypogon
The most ornate of the carpet sharks — a beard of branching skin flaps rings its whole head — and the signature reef find of Raja Ampat.
1 destination →

Tiger Sharks
Galeocerdo cuvier
The big, blunt-nosed generalist of warm seas — striped when young, apex when grown. On managed dives it is slow, curious and unnervingly close.
2 destinations →

Whitetip Reef Sharks
Triaenodon obesus
The slim reef shark that sleeps by day and hunts by night — the one you find stacked motionless under a ledge, white-tipped fins and all.
1 destination →

Bull Sharks
Carcharhinus leucas
The thickset requiem shark that swims up rivers — and the reason the Riviera Maya has a winter shark season.
1 destination →

Epaulette Sharks
Hemiscyllium ocellatum
The shark that walks — a small, patient reef-flat hunter that uses its fins as legs and can outlast almost any fish in water with no oxygen left in it.
1 destination →

Great White Sharks
Carcharodon carcharias
The largest predatory fish alive, and the one shark a diver cannot simply go and find — every reliable encounter on earth happens from a cage.
1 destination →

Nurse Sharks
Ginglymostoma cirratum
The Caribbean’s most-seen shark, and almost always asleep when you meet it — a heavy-bodied suction feeder that does its real work after dark.
1 destination →

Oceanic Whitetip Sharks
Carcharhinus longimanus
Once among the most abundant large animals on earth, now Critically Endangered — and met in open blue water with no bottom beneath you.
1 destination →

Bamboo Sharks
Chiloscyllium spp.
A small, slender, cat-like shark that spends the day jammed under a rock and the night walking the reef looking for crabs.
1 destination →

Silvertip Sharks
Carcharhinus albimarginatus
The grey reef shark’s larger, bolder cousin, edged in brilliant white and far more inclined to come and look at you.
1 destination →

Tawny Nurse Sharks
Nebrius ferrugineus
The Indo-Pacific’s nurse shark — a big, placid, day-sleeping suction feeder that turns into a serious nocturnal hunter.
1 destination →
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Bigeye Thresher Sharks
Alopias superciliosus
The deep-water thresher, with eyes built to look upward through 400 metres of darkness — and almost never seen by divers.
1 destination →

Port Jackson Sharks
Heterodontus portusjacksoni
A blunt-nosed, harness-marked bullhead shark that fills Sydney’s winter gutters and lays the strangest egg case in the sea.
1 destination →

Silky Sharks
Carcharhinus falciformis
A sleek, schooling open-ocean shark named for the feel of its skin, and most often met circling in the blue beneath a liveaboard.
1 destination →