Meet one of Koh Tao’s most lovable oddballs If reef fish had personalities, the blotched porcupinefish would be near the top of the list. Big eyes. A permanent surprised expression. Zero interest in looking streamlined. And somehow, despite being a round spiky potato with fins, they manage to be one of the most charming fish you can meet underwater. In Koh Tao, porcupinefish are always a crowd-pleaser. New divers love them because they look like a cartoon. Experienced divers love them because they have real character. And if you’ve dived Junkyard Reef, you may already know the local legend: Steve, the famous (not blotched) porcupinefish who has become a bit of a dive-site celebrity. What is a blotched porcupinefish? The blotched porcupinefish, also known as the black-blotched porcupinefish, is Diodon liturosus. It belongs to the porcupinefish family, which means it has two very famous skills: it can inflate when threatened, and it has sharp spines that stick out when it does. It lives across tropical and subtropical Indo-Pacific waters and is found around coral and rocky reefs. That makes Koh Tao a very good place to meet one. How to recognise one underwater Blotched porcupinefish are hard to miss once you know what to look for. They have: A chunky, rounded body Big, expressive eyes Shorter spines than some other porcupinefish species Dark blotches across the body rather than neat little spots A gentle, slightly confused look that makes divers fall in love immediately They can grow surprisingly large, even if the ones you see on the reef often look like they were designed by someone having a laugh. Why divers love porcupinefish so much Some reef fish are beautiful. Some are impressive. Porcupinefish are different. They are just… wonderful. They often hover in place with a slightly clumsy elegance. They tuck themselves into crevices during the day. They look straight at you in a way that makes it feel like a proper interaction. There is something very human about their expression, which probably explains why so many divers start naming them after one dive. They also tend to be quite photogenic. Not glamorous in a sleek barracuda kind of way. More in a “you are impossibly weird and I want a photo immediately” kind of way. What makes them a porcupinefish? Porcupinefish are not the same as pufferfish, although they are related and often get mixed up. The big differences are the long external spines and their body shape. When calm, the spines lie flatter against the body. When threatened, the fish gulps in water and inflates, making the spines stand out. It is a very effective way of telling predators to absolutely try someone else. This is also why divers should never chase, corner, or stress them. Inflating is a last-resort defence. It costs energy and puts the fish under strain. A good porcupinefish encounter is a calm one. What do blotched porcupinefish eat? These fish are built for crunching. They have a strong beak-like mouth that helps them feed on hard-shelled prey like molluscs, crustaceans, and other invertebrates. If something on the reef has a shell and thought that would protect it, a porcupinefish may have other ideas. They are mostly active around the reef looking for food, often around rocky bottoms and coral structures where tasty little creatures like to hide. Are they dangerous? For divers, not really. For the things they eat, definitely. Like several fish in their wider group, porcupinefish can be toxic if eaten and should be admired, not added to dinner plans. Underwater, though, they are peaceful animals. They are not aggressive. They are not going to come after you. The real risk is us stressing them by getting too close or trying to touch them. How to behave around a porcupinefish Keep your distance: give them space and let them choose whether to stay out or tuck away. Move slowly: quick hand movements and camera pushes can make them retreat. Never touch: hands off all marine life, always. Do not corner them: if they are in a crack or under a ledge, let them be. No chasing for photos: if they drift away, that is the end of the moment. The best encounters happen when you simply hover, breathe slowly, and let the fish get used to you. Steve: the porcupinefish of Junkyard Reef Now for the important part. Around Koh Tao, one porcupinefish has built a bit of a reputation: Steve from Junkyard Reef. If you have dived there, there is a good chance you have either seen Steve, heard about Steve, or surfaced to someone on the boat saying, “I think I met Steve.” That is the kind of local fame we are dealing with here. Steve has become one of those small Koh Tao underwater legends. Part of the fun of diving a site again and again is getting to know the regular residents, and Steve is one of the stars of the show. Divers love spotting him among the structures and growth at Junkyard Reef, and he is one of those fish that somehow feels familiar, even if you have only met once. It is exactly the sort of thing that makes local diving so special. The reef stops feeling like just “a dive site” and starts feeling like a neighbourhood. And every good neighbourhood has a character everyone knows. Why Junkyard Reef suits fish like Steve so well Junkyard Reef is packed with interest. It has structure, shelter, little corners, and loads of life moving through it. That creates a brilliant home for curious, reef-associated fish like porcupinefish. Artificial reefs and structured habitats can provide hiding places, feeding opportunities, and surfaces for marine growth. Over time, that turns a simple site into a lively underwater community. For divers, that means a site where every lap can show you something different. For Steve, it means excellent real estate. Where else might you see blotched porcupinefish around Koh Tao? While Junkyard Reef gets a lot of love thanks to Steve, porcupinefish can turn up on other reef and rocky sites too. Look around: ledges and overhangs small caves and cracks artificial structures quiet corners of busy reef sites They are often easier to spot once your eyes slow down a bit. Beginners tend to look for the “big famous things.” Experienced divers know that a lot of the best moments come from hovering near a wall and noticing the weird face looking back at you. Porcupinefish photo tips They are great subjects, but they reward patience more than pressure. Stay still: let them settle before lifting your camera too close. Focus on the eyes: those big eyes are what make the shot. Do not block their exit: always leave them a clear route away. Use good buoyancy: porcupinefish often hang near fragile reef structure. Take a few photos, then just enjoy it: not every encounter needs to become a full photo session. Fun facts about blotched porcupinefish They can inflate by taking in water, making themselves much bigger and much spikier. Their teeth are fused into a strong beak for crunching hard prey. They are found across a wide Indo-Pacific range. Despite looking slow and silly, they are well adapted to reef life. They may not be the fastest fish on the reef, but they are easily among the most memorable. Why wildlife spotlights matter It is easy to focus only on whale sharks, turtles, or the big schools. But part of what makes diving in Koh Tao so fun is all the smaller personalities that give each site its own flavour. A porcupinefish like Steve can become just as much a reason to love a dive site as any headline species. When divers connect with individual animals and local reef stories, they usually become more relaxed, more observant, and more respectful underwater. That is good for everyone: the divers, the guides, and the reef itself. Come meet Steve for yourselfIf you want to see why porcupinefish are such a favourite, come dive with us in Koh Tao. We love pointing out the local characters, and Junkyard Reef is always a fun one for fish with personality.Whether you are brand new to diving or already have a few hundred dives under your belt, there is something special about finding a fish everyone seems to know by name. Message Phoenix Divers and come meet Steve.Get in touch