Meet the three pufferfish species you can see diving Koh Tao — the Giant Puffer, the Porcupinefish (including Steve, the Junkyard's celebrity) and the Seal-faced Puffer — plus where to find them and how to interact responsibly.
13 May 2025 · updated 27 February 2026 · by Bryan Roseman
In short. The pufferfish Koh Tao divers encounter include three fascinating species: the gentle Giant Puffer, the celebrity Porcupinefish named “Steve”, and the endearing Seal-faced Pufferfish. These charismatic underwater residents, with their expressive eyes and unique defence mechanisms, have become some of the most beloved marine encounters for divers exploring Thailand’s diving capital.
The waters surrounding Koh Tao host an extraordinary cast of underwater characters that captivate divers from around the world. Among these marine personalities, the island’s pufferfish species stand out as some of the most charming and memorable encounters. With their bulbous bodies, perpetual “smiles” and quirky behaviours, these fascinating fish have earned a special place in the hearts of both novice and experienced divers exploring this Thai diving paradise.
Each pufferfish species around Koh Tao possesses unique characteristics that make them remarkable underwater encounters. From the impressive Giant Puffer cruising reef edges to the friendly resident Porcupinefish “Steve” at the Junkyard dive site, these creatures showcase the incredible diversity and personality of marine life in these tropical waters.
Use these four clues to identify which pufferfish species you encountered during your Koh Tao dive:
Large, smooth, white-starred and cautious? That’s a Giant Puffer. Medium, black-spotted, spiny and curious? A Porcupinefish. Small, smooth, with dark blotches and browsing the reef? A Seal-faced Pufferfish. The species profiles below give you the full picture.
Arothron stellatus
The gentle giant of Koh Tao’s pufferfish family, easily recognised by its impressive size and star-like white spots covering a darker background.
Best spots: Twins, Mango Bay, White Rock – usually found cruising along reef edges and sandy areas.
Diodon hystrix
The most iconic pufferfish species in Koh Tao, famous both for their spiky defensive capabilities and for the celebrity resident “Steve” at the Junkyard.
Best spots: the Junkyard (home to Steve), White Rock, night dives around most sites.
Arothron nigropunctatus
The most endearing species, with its distinctive “pouty” seal-like face and relatively rare appearances around Koh Tao’s dive sites.
Best spots: Japanese Gardens, Twins, Shark Island – they prefer shallow to mid-depth areas with healthy coral growth.
No discussion of pufferfish in Koh Tao would be complete without introducing “Steve”, the remarkable Porcupinefish who has become a local celebrity at the Junkyard dive site. Unlike his more cautious relatives, Steve has developed an extraordinary comfort level with human visitors, often approaching divers with genuine curiosity rather than keeping the typical defensive distance.
Named by local dive guides around 2017–2018, Steve has been observed growing from a juvenile to a mature adult Porcupinefish over several years. His friendly behaviour isn’t the result of feeding or handling – practices strongly discouraged by responsible dive operations – but rather a natural individual personality trait combined with learned comfort around respectful divers.
Steve’s territory: the Junkyard artificial reef site on Koh Tao’s western side, created from purposely placed structures and items that have been transformed into thriving marine habitats.
| Dive site | Pufferfish species | Best time | Notes |
|---|---|---|---|
| The Junkyard | Porcupinefish (Steve!) | All day | Almost guaranteed sightings, artificial reef environment |
| Japanese Gardens | All three species | Morning/afternoon | Beginner-friendly, shallow site perfect for Seal-faced Puffers |
| Twins | Giant Puffer, Seal-faced | Early morning/late afternoon | Giant Puffers cruise between the twin pinnacles |
| White Rock | All three species | Variable | Porcupinefish rest in crevices during the day |
| Shark Island | Seal-faced Pufferfish | Daytime | Shallow depth suitable for diving and snorkelling |
| Night dives | Porcupinefish (active) | After sunset | Best time to observe natural foraging behaviour |
Warning: tetrodotoxin. All pufferfish species contain tetrodotoxin, one of nature’s most potent neurotoxins, with no known antidote. While this poses no danger to divers who observe these creatures respectfully, it reinforces the absolute importance of the “look but don’t touch” principle. The toxin is primarily concentrated in the internal organs but is also present in the skin. Never attempt to handle, feed or stress these fish into inflating – they can only “puff up” 3–4 times before potentially fatal stress occurs.
These guidelines help ensure both your safety and the wellbeing of these remarkable creatures:
Despite their toxic defences, pufferfish face numerous challenges in Koh Tao’s waters and throughout their range:
Local dive operators and conservation organisations promote responsible interaction guidelines that help protect these charismatic creatures while allowing sustainable tourism encounters.
Ready to encounter Koh Tao’s charming underwater puffers? La Bombona Diving offers guided dives to the best pufferfish-spotting locations around Koh Tao, including the Junkyard and beginner-friendly Japanese Gardens, with small groups, conservation-focused diving practices and both day and night dives. Start with a Try Dive (2,500 ฿, all equipment included) to meet Koh Tao’s pufferfish, or get certified to explore all the best sites.
Diving with pufferfish is completely safe when following basic responsible diving principles. The tetrodotoxin is primarily concentrated in internal organs and cannot harm you through water contact or proximity. The toxicity only poses risks if the fish is consumed or if someone is cut by their teeth or spines. Koh Tao dive guides are well trained to ensure appropriate wildlife interactions.
Steve's friendly behaviour developed gradually through positive interactions with respectful divers over several years. Named by local guides around 2017–2018, his curiosity toward humans represents natural individual personality traits rather than conditioning through feeding or handling. Some individual fish, like mammals, simply have bolder, more curious personalities that make them comfortable around a non-threatening human presence.
Many pufferfish, particularly Porcupinefish and Seal-faced Puffers, can be observed while snorkelling at shallow sites like Japanese Gardens and Aow Leuk. However, certified divers have access to more locations, including the Junkyard where Steve resides, and better opportunities to encounter Giant Puffers, which prefer slightly deeper water. If you're planning your trip, check out our guide on how to get to Koh Tao from anywhere in Thailand.
Pufferfish rarely inflate when encountering respectful divers. Inflation is their ultimate defence mechanism, used only when seriously threatened with no escape option. This energy-intensive response can be extremely stressful – they can only inflate 3–4 times before potentially fatal stress occurs. Responsible divers keep an appropriate distance to avoid triggering this defensive behaviour.
Pufferfish are year-round residents, so there's no specific "pufferfish season". However, March through October generally offers the best diving conditions, with calmer seas and better visibility, enhancing the overall experience of spotting and photographing these charismatic creatures. Steve at the Junkyard is reliably present throughout the year, though wildlife sightings can never be 100% guaranteed on any particular dive.
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