PJ is the home to PJ (or now Zen) Beach which is the ultimate Muck Diving site of Bali. Muck diving is exactly what it sounds like - diving in mud and looking for all kinds of creatures living there. You'll rarely spot anything bigger than a Remora here though I did once find the carcass of a large sting ray here.

The bottom composition is black volcanic sand and this is littered with small button corals. Every so often you'll find an island of life in the form of an Anemone, aggressively defended by its resident Clown Fish (serisouly, they may be really small but they're totally fearless). In the sand (if you look hard) you'll find loads of weird and wonderful creatures, the most exotic being the Mimic Octopus. Every so often you'll also come across some sunken concrete blocks which are home to juvenile Scorpion and Lion fish as well as Mantis Shrimps.

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Technical Diving with PADI
Emergency First Response
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