Often scuba divers focus on tiny critters, schools of fish, or jumbo-sized creatures like whales, dolphins, and sharks. This leaves corals to get lumped together under a single term ‘coral reef’ which is far too general to describe the hundreds of individual coral species waiting to be discovered.
Corals are the foundation of the marine environment and it’s a rewarding experience to scuba dive with the intention of looking for corals. We’ve put together this list of 20 corals which you can start looking for while diving in Indonesia. You will also find these corals throughout the entire Indo-Pacific.
Scuba Diving Indonesia
Indonesia is one of the world top scuba diving destinations because of the abundance and diversity of marine life. At first, scuba diving in Indonesia can be overwhelming with so much new to look at, but after a few dives once you’ve adjusted to the underwater world, take a moment and turn your eyes to the reef, and start searching for corals. Huge colony of Lobophyllia corals in the Bunaken National Park – Sulawesi Indonesia
Corals are a diverse group of animals with hundreds of individual species. The reason I love searching for corals is that each coral can look vastly different than corals of the same species so even if you’ve seen a coral once, you never know where a biggest brighter colony is hiding.
Coral growth is influenced by the location and conditions it is found growing on the reef. So corals living in a high light or high flow area will look different than corals found below 20 meters.
For example a branching coral found living in high-flow or surge area will focus energy on creating a solid encrusting base before it begins to forms branches. The same coral found living in a shallow lagoon with very little current would have a smaller base with more branches. The coral on the left is growing on the edge of a wall in an area of high current and has lots of tissue encrusting on the rock with few branches. The coral on the right is growing in a shallow low current reef and has a compact shape with many branches. However, both corals are the same species which have short almost triangular shaped branches.
Coral Genus Identification
This shape-shifting ability can be confusing for some who are just learning to identify corals species. If this is your first time trying to identify corals, it is best to start at the genus level before trying to identify coral species.
For example, Montipora is a common genus of coral from Indonesia. Montipora corals can be recognized from having tiny corallites which are embedded in the surface of the coral. Small flowering polyps are usually always visible and often a different color from the coral’s tissue. The surface of the coral is covered in short smooth ridges or bumps which are loosely connected or completely disconnected from one another.
When you have the visual image in your head of Montipora it is easy to spot this abundant genus regardless of the individual species. For Montipora, there are over fifty individual species, which are encrusting, platting, or branching. To identify this coral to the species level you will need to take wide-angle pictures of the colony and close-ups of the corallites, you may also need to measure the corallite size to get a perfect match. *Montipora can be confused with Porites which also has small corallites that look like pores in the surface of the coral. However, Porites, for the most part, lacks the smooth bumpy ridges characteristic of Montipora.
Coral Identification Basics
The corals listed below are a general representation of each genus. Many of these coral types have dozens of species which can look different than my photos. This list is meant to be a starting place for your coral exploration.
If you are just starting out the best thing to do is look for common traits shared amongst a certain genus of corals. Start with memorizing a few corals to recognize underwater and scuba diving becomes a never-ending treasure hunt! If you want to learn more about basic coral biology and helpful term for coral identification check out my article on Scuba Diver Life Coral Biology I & Coral Biology II
If you are interested in learning more about a particular species let me know in the comment below, or check out some of the online resources for species identification. Coral Identification Resources – Coral Hub, Coral Finder, AIMS Coral Fact Sheets, Corals of the World
1. Blastomussa
Blasstomussa is a small cryptic coral that can be found in muck diving habitats, or on dark walls, and caves. There are two species of Blasstomussa, one has large polyps (pictured above) which are 2-3cm or 1 inch in diameter. The second species has polyps which are smaller around 1cm in diameter. The polyps of both species are smooth in the center near the oral disk becoming bumpy and inflated near the rim. Blastomussa corals can be bright reds, green, purple, pinks, orange, and some colonies can have three or more colors in a single polyp.
2. Catalyphyllia
Catalyphyllia is a stony coral with elegant tentacles, it’s no wonder the common name for this coral is the Elegance coral. The skeleton of this coral is a meandering shape and can be found resting on the seafloor usually in muck habitats. Catalyphyllia is a pale color with striped pattern in the center of the polyp with pink, purple, blue and green accents. Catalyphyllia corals can be up to 30 cm or 12 inches across and tentacles a few cm long.
3. Caulastrea
Caulastrea is a small coral with little trumpet-shaped corallites. Each Caulastrea stalk can a few cm long and have one of two corallites on the end. The corallite at the end is around 2cm or .5inch wide depending on the species. If you look close you can see some corallites which are pinches in the center like a figure eight, this is how a single corallite slowly splits in two. This coral can also be green, red, and, white, and brown, with some having all three colors.
4. Euphyllia
Euphyllia corals are easy to spot because of their hammer shaped polyps. The skeleton can be branching or meandering forming long deep walls. However, there are around nine species of Euphyllia and only three have this type of polyp. The other types of Euphyllia have long tentacles covered in bumps like frog eggs, or long polyps like a torch. Learn to spots this coral Euphyllia ancora and you’ll be on your way to becoming a master Euphyllia spotter.
5. Galaxea
Galaxea coral is common throughout the Indo-Pacific. You can notice this coral because of the crown shaped corallites. There are seven species of Galaxea and some can be encrusting and some can be branching. At night Galaxea will put out long stinging tentacles and when you find this coral you will notice other species keep their distance because Galaxea will sting anything it can reach.
6. Gonipora
Gonipora has long flowing polyps that look like tiny underwater flowers. But don’t be fooled this fleshy coral has a hard skeleton often shaped like a ball. Gonipora corals have 24 tentacles on the end of each polyp, and can be found in nearly every color imaginable. Gonipora looks similar to Alveopora, however, Alvepora has 12 tentacles, so if you find this coral and it has too many tentacles to count you’ve got yourself a Gonipora.
7. Heliofungia
Heliofungia might look like a sea anemone, but this coral has a hard skeleton shaped like a disk. Heliofungia has long tentacles are most often green or yellow and can have a striped pattern on the coral tissue. Take a closer look between the tentacles and if you’re lucky you could find a small white pipefish that only lives with the Heliofungia coral.
8. Isopora
Isopora palifera is easily one of the most recognizable corals throughout the Indo-Pacific. If you are just starting to learn coral identification Isopora is one of the easiest corals to spot. Isopora forms robust colonies with thick blades, and the entire colony is covered in smooth, rounded corallites. The blades are upright stretching to the surface and the tops of each blade are normally a pale color.
9. Lobophyllia
Lobophyllia is a common coral, however, colonies of this coral can grow to extraordinary size. Lobophyllia colonies are made up of large fleshy polyps that grow together like lobes. The polyps can be compact and barely cover the corals skeleton or they can be large and fleshy covering the skeleton like a carpet. Lobophyllia can be found in all sort of colors with some common species being grey, brown, white and red.
10. Montipora
Montipora is one of the most abundant corals with over fifty species in the Indo Pacific. Montipora can be branching, encrusting, or form thin plates. The way to recognize Montipora is the small corallites which are embedded in the surface of the coral. This coral comes in a variety of colors and the rarest corals to look for have three or more colors in the same coral.
11. Mycedium
Mycedium is one of the first corals I learned to identify. You can easily recognize this coral by the cup or nose-shaped corallites that always face towards the edges of the colony. Mycediums will have a large corallite in the center of the colony, and the coral grows outwards from that spot. There are five species of Mycedium and the easiest to identify are Mycedium elephantotus which has the largest corallites and can cover large sections of reef. The second is Mycedium robokaki which forms plates with small corallites in a contrasting color from the coral tissue.
12. Oxypora
Oxypora can be easy to spot if you know what to look for. This coral forms thin plates in a variety of colors. There are five species of Oxypora all with small poorly developed corallites. This coral is similar to Echinopora, Mycedium, and Echinopyllia, but while they look similar from far away the corallites of Oxypora are the smallest of all these thin plating species.
13. Pachyceris
Pachyseris is an interesting coral that has narrow ridges a few millimeters above the surface of the colony. The ridges can be long and narrow or short and contorted. There are five species of Pachyseris and this coral can be plating, encrusting or branching. Something you can find large areas covered in thin plating Pachyseris. This coral lacks are corallite structure and instead has septa-costea which run perpendicular to the narrow ridges.
14. Pectinia
Pectinia lactuca is easy to recognize because of the deep elongate valleys and walls. Most valleys can be traced from the colony center to the margins of the colony. There are nine species of Pectinia, however P. lectuca is the most distinct. The other species can be branching or boulder. The tissue is usually puffy which is a characteristic of Pectinia corals.
15. Plerogyra
Plerogyra is a common coral that forms smooth pearl or grape shaped bubbles. This could easily be mistaken for a soft coral because of the soft flowing texture of the bubbles. However, underneath this coral have a hard skeleton which can be branching or for thick meandering walls. Bubbles can be 1 cm (.5 inch) or more in diameter depending on the species some bubbles being closer to 3cm or 1 inch in size.
16. Pocillopora
Pocillopora is a super common coral, you will find it from the shallowest to the deepest parts of the reef. There are almost twenty species of Pocillopora but they all have the same bumpy branches. Sometimes the branches are densely packed or wide and spread out. It depends on the species and where on the reef you find the coral.
17. Seriatopora
Seriatopora is a small branching coral that has fuzzy polyps. The branches can have smooth branch tips or pointed branch tips. The way to identify this coral is by looking at the placement of each polyp. In Seriatopora coral all the polyps line up in a neat row.
18. Symphyllia
Symphyllia is a distinct coral with wide ridges with valleys around 2-3 cm (1 inch) wide. The coral tissue is thick and hides the skeleton. Valleys can be a different color for the ridges, and extra special colonies have a third color for the polyps.
19. Trachyphyllia
You know you’ve hit the coral motherload when you find a Trachyphyllia coral. You can find this coral in muck diving habitats. This coral is a single large polyp that can be shaped like a figure eight or have several different folds. This coral is often striped with a rainbow of colors. Pro tip is to shine a UV light at this coral to really make it pop.
20. Turbinaria
Turbinaria is a common coral from the Indo-Pacific. You can recognize this coral from the tube shaped corallites. There are more than 10 species of Turbinaria and they all have smoothe tissues with tubular corallites some biggest than others. The easiest species to spot is the bright brown and yellow Turbinaria reniformis and Turbinaria peltata which forms large greyish plates with wide flowering polyps.
