Tag: Local Marine Life

A field-guide to the local marine life of the Koh Phangan, Koh Tao, Angthong Marine Park area of the Gulf of Thailand.

All species will be divided initially into one of the following four main groups:

  • Pelagic -

    This section contains those species that live predominantly in the water column, away from reef systems or the bottom.

    There are many species which may frequent the other zones from time to time, but which are undoubtedly Pelagic by nature.

    An excellent example of this is the Whale Shark (Rhincodon Typus) which traverses the world's tropical oceans, but may appear at shallow inshore reefs in order to exploit synchronized spawning events.

  • Benthic -

    This section contains marine species that live, or are most active in the Benthic zone where "Benthic" is generally considered to be the "bottom layer of a body of water"

    Whilst true Benthic species such as Stingrays are almost confined to the sea floor, a large variety of species classed as Demersal fish are included also.


    Demersal fish differ slightly from "true" Benthic species in that whilst they are active on the sea floor, they may inhabit other areas such as coral reefs.


    A very good example of a Demersal species are the members of the Goatfish (Mullidae) family. This family spend almost all of their active life foraging for food on the sea floor, with their downward facing mouths and chemo-sensory "barbels" probing the sand for small invertibrates.

    However, when not foraging, it is a very common sight to find certain species resting on top of large coral formations within the reef zone

    .

  • Reef-Dwelling -

    This section is dedicated to species predominantly associated with coral reefs. Although there are some species which are often thought of as reef fish, they may in fact belong with one of the other categories.

    A good example of these are the Stingrays (Dasyatidae), which are often found sheltering underneath large coral formations (particularly during the daytime). However, there can be little doubt that Stingrays and the like are perfect examples of Benthic species.


  • Unidentified -

    This section contains species which cannot be identified with a reasonable degree of certainty.

    There will be instances where a particular species appears within a known family, but also appears in the Unidentified section. For example:

    If a fish has been photographed, and clearly belongs to the Wrasse (Labridae) family, but the exact species cannot be determined, it will appear in both the Wrasse AND Unidentified sections of the this gallery.

    In some cases, the photographs may be of poor quality due to the circumstances under which they were taken eg. poor visibility/lighting, fast moving species, difficulty in approaching, etc.

    As with all of the photographs in the Marine Life gallery, comments, observations or recommendations are most welcome, particularly regarding unidentified/misidentified species.


A rating system has been used with each photo to show the degree of certainty regarding identification.


This guide is intended as an aid to amateur enthusiasts, rather than a definitive reference source. Therefore, if you think that a species has been incorrectly identified, please feel free to leave a comment. User input is greatly appreciated.

A field-guide to the local marine life of the Koh Phangan, Koh Tao, Angthong Marine Park area of the Gulf of Thailand.

All species will be divided initially into one of the following four main groups:

  • Pelagic -

    This section contains those species that live predominantly in the water column, away from reef systems or the bottom.

    There are many species which may frequent the other zones from time to time, but which are undoubtedly Pelagic by nature.

    An excellent example of this is the Whale Shark (Rhincodon Typus) which traverses the world's tropical oceans, but may appear at shallow inshore reefs in order to exploit synchronized spawning events.

  • Benthic -

    This section contains marine species that live, or are most active in the Benthic zone where "Benthic" is generally considered to be the "bottom layer of a body of water"

    Whilst true Benthic species such as Stingrays are almost confined to the sea floor, a large variety of species classed as Demersal fish are included also.


    Demersal fish differ slightly from "true" Benthic species in that whilst they are active on the sea floor, they may inhabit other areas such as coral reefs.


    A very good example of a Demersal species are the members of the Goatfish (Mullidae) family. This family spend almost all of their active life foraging for food on the sea floor, with their downward facing mouths and chemo-sensory "barbels" probing the sand for small invertibrates.

    However, when not foraging, it is a very common sight to find certain species resting on top of large coral formations within the reef zone

    .

  • Reef-Dwelling -

    This section is dedicated to species predominantly associated with coral reefs. Although there are some species which are often thought of as reef fish, they may in fact belong with one of the other categories.

    A good example of these are the Stingrays (Dasyatidae), which are often found sheltering underneath large coral formations (particularly during the daytime). However, there can be little doubt that Stingrays and the like are perfect examples of Benthic species.


  • Unidentified -

    This section contains species which cannot be identified with a reasonable degree of certainty.

    There will be instances where a particular species appears within a known family, but also appears in the Unidentified section. For example:

    If a fish has been photographed, and clearly belongs to the Wrasse (Labridae) family, but the exact species cannot be determined, it will appear in both the Wrasse AND Unidentified sections of the this gallery.

    In some cases, the photographs may be of poor quality due to the circumstances under which they were taken eg. poor visibility/lighting, fast moving species, difficulty in approaching, etc.

    As with all of the photographs in the Marine Life gallery, comments, observations or recommendations are most welcome, particularly regarding unidentified/misidentified species.


A rating system has been used with each photo to show the degree of certainty regarding identification.


This guide is intended as an aid to amateur enthusiasts, rather than a definitive reference source. Therefore, if you think that a species has been incorrectly identified, please feel free to leave a comment. User input is greatly appreciated.

Alan's picture
Sail Rock's amazing marine life!

A diver swims headlong into a huge school of Big-EyeSnapper(Lutjanus lutjanus) at

Alan's picture
Moon Wrasse (Thalassoma lunare) - dominant male with subordinates

A single dominant male Moon Wrasse (Thalassoma lunare) carefully guards its harem of "intermediate phase" females (and subordinate males) during a period of spawning at Sail Rock.

Alan's picture
Narrow-Barred Spanish Mackerel (Scomberomorus commerson)

This Narrow-Barred Spanish Mackerel (Scomberomorus commerson), photographed at around 25m off the Camel Humps on Sail Rock's south-west corner, appears to have had a very lucky escape!

Alan's picture
A large adult Talang Queenfish (Scomberoides commersonnianus) at Sail Rock

A large adult Talang Queenfish (Scomberoides commersonnianus) at Sail Rock.

Alan's picture
Black-Line Shrimp Goby (Myersina Nigrivirgata) - Variation 2

This Black-Line Shrimp Goby (Myersina nigrivirgata), photographed at Mae Haad/Koh Ma, also shows the "typical" colouration for locally occurring specimens, although the narrow bands that occasionally t

Alan's picture
Black-Line Shrimp Goby (Myersina Nigrivirgata) - Variation 1

This Black-Line Shrimp Goby (Myersina nigrivirgata), photographed at Mae Haad/Koh Ma, shows the "typical" colouration for specimens in local waters.

Alan's picture
Lined Butterflyfish (Chaetodon Lineolatus) at Sail Rock

A Lined Butterflyfish (Chaetodon lineolatus) above the East Pinnacle at

Alan's picture
Banded Shrimp Goby (Cryptocentrus Cinctus) - Yellow and Dark Variations

This photograph from Tanote Bay, Koh Tao shows the fairly uncommon combination of both the yellow/gold and darker brown variations of Banded Shrimp Goby (Cryptocentrus cinctus) together.

Alan's picture
Lagoon Shrimp Goby (Cryptocentrus Cyanotaenia)

This Lagoon Shrimp Goby (Cryptocentrus cyanotaenia), photographed at Mae Haad/Koh Ma reef, shows yet another slight colour variation.

Alan's picture
High-Finned Blenny (Petroscirtes Mitratus) - female

This High-Finned Blenny (Petroscirtes Mitratus), probably a female due to the relatively short first dorsal spines, was patrolling a small, sparsely weeded area just beside Chaloklum pier.