Invertebrate
Blue-ringed octopus
Hapalochlaena sp.
A small octopus that flashes iridescent blue rings when threatened; its bite carries tetrodotoxin and can be fatal. A prized macro find on sand and rubble, often on night dives — observed only, never handled.
- Max size
- ~10–20cm including arms
- Habitat
- Sand, rubble and reef; frequently found on night dives
Best places to dive with Blue-ringed octopus
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
One of several rare cephalopods on the muck sites alongside mimic octopus and wonderpus; a prized but unpredictable find.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Regularly found on muck sites and night dives, emerging after dark; small and easily missed without a spotter.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Found on the sandy muck sites such as Secret Corner; a prized find but small and cryptic, so encounters are occasional rather than reliable.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Present year-round but small and cryptic; sightings depend on a sharp-eyed guide and are never guaranteed.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
A macro and night-dive find on the sand and rubble sites; venomous, observed only.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Found on shallow muck and around the Sabang wrecks, most often on night dives. Small and venomous; not seen every dive.
| Month | Likelihood |
|---|---|
| January | rare |
| February | rare |
| March | rare |
| April | rare |
| May | rare |
| June | rare |
| July | rare |
| August | rare |
| September | rare |
| October | rare |
| November | rare |
| December | rare |
Present but a lucky find, usually on sand and rubble patches; venomous, so it is observed, not handled.
Sources & last checked
Checked July 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- Malapascua Marine Life — Thresher Shark Divers
Note on the data: The genus is not assessed on the IUCN Red List, so conservationStatus is recorded as unknown rather than invented.