On a Flagship Aruba cruise you're going to see a lot of fish at the SS Antilla wreck, in the shallows of Boca Catalina, along Malmok Reef. Most guests come up from the water asking the same question: "What was that?" This guide covers the species you're most likely to encounter on our tours, and the fastest way to tell them apart when you're floating above a reef with a mask full of colour.
The Aruba Advantage: Visibility Does Half the Work
Identifying fish in murky water is hard. Identifying them in Aruba is not. Water visibility on our snorkel sites regularly exceeds 25–30 metres, which means you get a clear, well-lit look at almost everything you encounter. There's no squinting through green water trying to make out a shape you'll often see fish from the surface before you even get in.
That clarity is one reason Aruba's reefs are so popular with snorkelers who want to actually learn what they're looking at. It's also why so many guests on our Afternoon Snorkel Tour end up spending longer in the water than they planned.
🐠 Our crew knows these fish by name. If you spot something you can't identify, ask whoever's in the water with you our team has been snorkeling these exact sites for years and can name almost anything you'll encounter at the Antilla or Boca Catalina.
Four Things to Look at First
When you see a fish you don't recognise, run through these four things quickly in this order. It takes about five seconds and will narrow down almost any species to its family before the fish swims away.
1. Body Shape
Is it tall and disc-shaped? That's an angelfish, butterflyfish, or surgeonfish family. Long and thin like a stick? Trumpetfish or needlefish. Flat and diamond-shaped gliding across the sand? A stingray. Rounded and inflatable-looking? Pufferfish or balloonfish. Body shape tells you the family colour and markings tell you the species.
2. Colour Pattern
Focus on the pattern more than the exact colour patterns stay consistent even as fish age or change sex, and water depth can shift how colours appear. Horizontal stripes, vertical bars, solid blocks of colour, spots each pattern is associated with specific groups. The five bold black vertical stripes on a sergeant major, for example, make them unmistakable even at a distance.
3. How It Swims
Behaviour is often faster to read than colour. Parrotfish row through the water with their pectoral fins in a distinctive, almost bird-like motion. Trumpetfish hover nearly vertical, completely still, waiting to ambush prey. Barracuda face into the current with a watchful, barely-moving stillness that's immediately recognisable. French grunts hover in tight, motionless clusters under ledges during the day. Once you know these behaviours, you can identify a species from ten metres away.
4. Where It Is on the Reef
Different species occupy different zones. If a large fish is resting on the sandy bottom under a coral overhang, it's almost certainly a nurse shark or a large grouper. If something is hovering in mid-water above the wreck, it's likely a jack or barracuda. If it's nipping at coral surfaces, it's probably a parrotfish or damselfish. Location on the reef is a strong clue that most beginners overlook.
Fish You'll Almost Certainly See on a Flagship Aruba Cruise
These are the species our crew encounter on virtually every trip at the SS Antilla, at Boca Catalina, and along Malmok Reef. Read through before you get on the boat and you'll be naming them from the first minute in the water.
Small, oval-shaped, with five bold black vertical stripes on a yellow-white body. You'll see them in enormous schools swirling around the upper sections of the Antilla wreck. Easy to spot, hard to miss.
Yellow diagonal stripes on a silver body. They gather in large stationary clusters under the ledges and overhangs of the Antilla during the day sometimes hundreds of them, completely still, like a living curtain.
Electric blue-yellow body, tall disc shape, and a distinctive dark "crown" marking on the forehead. One of the most visually striking fish on the reef usually seen in pairs, moving slowly along coral heads.
Bright mosaic of green, blue, and pink scales, with a beak-like fused mouth used to scrape algae off coral. You'll hear them before you see them the crunching sound is unmistakable. Their rowing fin motion makes them easy to track.
Extremely long and thin like a floating stick with a tiny mouth. Hovers vertically near sea fans and coral branches, waiting to ambush smaller fish. Colours vary from brown to bright yellow. Easy to swim right past if you're not looking.
Uniform green-yellow, thick, and muscular. Usually spotted with just the head poking out of a hole in the wreck, mouth opening and closing rhythmically (that's breathing, not aggression). Don't reach into holes they bite if cornered.
The Best Tip: Stop Moving
If there's one thing that separates guests who see everything from guests who see almost nothing, it's this: the best snorkelers stay still. When you fin aggressively through the water, fish scatter. When you float motionless on the surface, they come back and within a minute or two they completely ignore you.
Find a sandy patch between coral heads at Boca Catalina, stop kicking, and just watch. The reef comes alive around you. Fish emerge from crevices. Turtles continue feeding. A trumpetfish drifts into your field of view from nowhere. It's a completely different experience from chasing things around the reef.
Our crew will tell you this before you get in the water, but it's worth saying here: the Antilla and Boca Catalina reward patience more than effort. Float, look, and let the reef come to you.
Take photos, look them up later. Even a blurry shot gives you something to work from. The iNaturalist app can identify species from a photo and logs your sighting for scientific research a satisfying extra layer to the experience.
Sea Turtles: A Special Mention
Green and hawksbill turtles feed regularly in the sea grass beds at Boca Catalina. They're not guaranteed on every trip, but they're common enough that our crew will actively look for them when we anchor there. When you find one, the rule is simple: stay calm, keep at least 2 metres of distance, and don't touch or chase. A turtle that feels safe will keep feeding calmly and give you several minutes of extraordinary observation. A startled turtle is gone in seconds.
Turtles need to surface for air roughly every few minutes. If one is heading up, clear a path never block it. Our crew will brief the whole group before entering the water at Boca Catalina, so everyone knows the protocol before it matters.
See Aruba's Reef for Yourself
The fish are there the sergeant majors at the Antilla, the angelfish at Boca Catalina, the eagle rays at Malmok. Our crew will be in the water with you, naming everything you see. All the gear is included.