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Coral spawning 2014 26 Apr 2014

Posted by cat64fish in Tales from the N2 bar.
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No time to write up this year’s trip, but others have already done so!

My Flickr photos of the dive trip: https://www.flickr.com/photos/cat64fish/sets/72157644113430962/

Tan Chuan Jin’s Facebook post: https://www.facebook.com/media/set/?set=a.708356862540425.1073741902.182928775083239&type=1

WildSingapore’s write up: http://wildshores.blogspot.sg/2014/04/mass-coral-spawning-2014.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+WildShoresOfSingapore+%28wild+shores+of+singapore%29#.U1tn46JIphQ

Stalking a Blue-tailed Dartfish 2 Jan 2013

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Zee and Debby have a paper out in Nature in Singapore, documenting the observation of a new fish record for Singapore: the Blue-tailed Dartfish (Ptereleotris hanae). Check out the video link the electronic version of the paper, showing a pair of them at Palau Hantu. A really beautiful fish, but shy and elusive; up till Zee asked me for a still image of the fish, the video was our best record for its occurrence in Singapore.

I’d seen the fish twice before at Hantu, once at the western side, and once at the northern tip near Bukom; both times, I didn’t get a useable image – being a particularly shy fish, getting up close and personal with it was very difficult, and the sediment in the water made long-distance shots almost impossible. The third time was the charm though, because this time, the fish was out and about, apparently busy feeding on plankton. After several attempts at long-distance (long distance here meaning more than 1.5m away) proved unsuccessful, I decided to just acclimatize the fish to my presence by just hanging around its feeding range, and trying my best to look busy taking photos of anything else except the fish. The ruse seemed to work (or maybe it was just very hungry!) – after about 15mins (and my inching in about half a meter), the fish seemed to ignore me and my buddy’s presence.

Taking this once-in-a-blue-moon opportunity, I happily snapped away before cold and lack of air ended our encounter. Of the 2 dozen or so images I took, only about a quarter of them turned out to be useable, and the best one was chosen for the paper.


Yay! 😀

Angelfishes of Singapore 23 Aug 2012

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Singapore has four species of angelfish that I know of:

1. Chaetodontoplus mesoleucus (Vermiculated Angelfish)
Photo by Khoo Minsheng

A common fish on our reefs; not abundant, but usually a pair can be seen on a dive. Commonly mistaken for a butterflyfish.

2. Pomacanthus annularis (Blue Ring Angelfish)
Not commonly seen on a reef; there used to be one resident at the artificial reefs I studied off Pulau Hantu. Adults have a distinctly white tail and blue diagonal stripes; juveniles have alternating iridescent light blue and dark stripes.

3. Pomacanthus imperator (Emperor Angelfish)
Photo not taken in Singapore!

Only seen once before at an artificial reef site off Pulau Hantu.

4. Pomacanthus sexstriatus (Six-barred Angelfish)

Not so common on our reefs, but exciting to see them when they appear. Typically wary of divers, they will stay out in the open and eye-ball you if you keep calm and keep your distance.

Anyone know of more?

Low, JKY and LM Chou, 1992. Distribution of coral reef fish in Singapore. LM Chou and CR Wilkinson (eds.) 1992. Third ASEAN Science and Technology Week Conference Proceedings, Vol 6, Marine Science: Living Coastal Resources, 21-23 Sep 1992, Singapore. Dept of Zoology, National University of Singapore and National Science and Technology Board, Singapore.

Lim, KKP and JKY Low, 1998. A guide to common marine fishes of Singapore. Singapore Science Centre. 163pp.

Low, JKY and LM Chou, 1999. Fish community development at two types of artificial reefs in Singapore. Proc. 9th JSPS Joint Sem. Mar. Fish Sci. pp241-252, 1999.

Coral spawning 2012 27 Apr 2012

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The corals were at it again … mass spawning that is. Two years after the last El Nino bleaching, the mass spawners seem to have recovered from their ordeal and were popping up sperm and egg packets in an almost never-ending stream of orgiastic delight. Over three nights, researchers from NUS and NParks visited the Pulau Satumu reef to observe and document this event.

The conditions were almost perfect – there was almost no wind, waters were calm, and visibility was good (averaging about 4m). The sunsets before each dive were spectacular!

Sunset 1

Sunset 2

Sunset 3

The first night saw sporadic puffs of egg packets – nothing spectacular. The second night was more exciting – the first corals started spawning around 8.30pm, comprising mostly faviids, one or two Galaxeas, and a rare observation of a Diploastrea colony spawning – hard to miss, since it squirted its hard-to-see spawn into a researchers face! On the final night of our voyeuristic observations, even more corals spawned; it was a good thing there were 7 of us on the reef, which enabled us to not only capture multiple colonies spawning, but also to capture the entire spawning sequence of some colonies.

A Favites coral showing signs of “setting” (just prior to the release of the gametes, you can see the orange-coloured bundles rising to the mouth of the corallite).

Shortly after setting, the gametes are released; in this case, as an “explosion” of orange-coloured balls.

Other species, such as this Pectinia, release their spawn as irregularly-shaped lumps or strings.

The total of number of species that spawned during our observations is still being tallied, and will contribute to a world-wide effort to better document these events. Hopefully we gathered enough information for a small paper to written (I’ll update if there is one).

More images and videos can be found on my Flickr Coral spawning 2012 set.

Mega-fauna at Hantu 9 Nov 2011

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Hantu may be the most frequently dived spot in Singapore, but it still holds many surprises, including large Hawksbill Turtles ….


…. half-meter long pufferfish ….


… and the mythical meter-long batfish!

Rabbitfishes of Singapore 16 Sep 2011

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What kinds of rabbitfish do we have in Singapore? There are five species that I know of:

1. Siganus canaliculatus (White-spotted Spinefoot), a common species that seems to be seasonal; particularly abundant around year’s end. Found in the waters around Ubin and, in this case, at Cyrene Reef flat.

2. Siganus guttatus (Gold-lined Spinefoot) , a common reef species. I have photos from my old artificial site, but none digital, yet.

3. Siganus javus (Streaked Spinefoot), another common reef species, although it has been caught off Ubin before.

4. Signaus virgatus (Bar-head Spinefoot), a rare species, so far only seen around Pulau Satumu.
Taken at Pulau Satumu in Dec 2010.

5. Siganus vulpinus (Fox-face Rabbitfish), a very rare species. Seen once from the jetty at Pulau Satumu, on a day with very clear water. No image.

My first local sighting of a frogfish! 15 Sep 2011

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The post headliner says it all 😀

I’d only heard of frogfishes in Singapore, never having the luck to see one for myself. Thanks to Chay Hoon, who found this little fellow in a fish trap at Semakau, I now have an image of it as well!

This could be a Painted Frogfish (Antennarius pictus), on account of it’s slightly less warty skin (compared to a similar looking fellow, the Warty Frogfish, Antennarius maculatus).


What makes a dive special? 30 Aug 2011

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How do you rate a dive? I’ve always been of the opinion that “every dive is a good dive”, but what is “good”?

In this case, on my umpteenth trip to Hantu (28 Aug 2011), “good” was defined by the company, the 4m visibility and the encounters underwater:

1. The hugest batfish I’ve ever seen – I’m convinced it is an Orbicular Batfish (Platax orbicularis), although it could also be the Hump-headed Batfish (Platax batavianus), since both of them look very similar. You can gauge the size of the fish from the photographer (Eunice) behind it.


What’s even more surprising, is the remora that is swimming around its host – it was actually cleaning it as well! This cleaning behaviour has been reported for dolphins and whales, but this was the first time I saw it for a batfish.


2. As mentioned by others on the trip, Bonellas were out in force – and wherever a large number of nudibranchs are seen, some of them will be caught procreating! A little bit of “fencing” as the penises jockey for position ….


… before the participants settle down.


Other wild things were witness to the almost non-stop “snap snap snap” of our cameras:

3. A cuttlefish

4. An eel blenny (Congrogadus subducens)

5. A tiny goby and an extra large pistol shrimp (I am told that this pairing of large shrimp and small goby is unusual, since there is typically competition for larger shrimps by larger gobies)

6. A squat lobster in a featherstar

Finally, even “experienced” divers occasionally make mistakes – in my case, I touched something that i shouldn’t have (“Don’t touch what you don’t know”!), and got my finger “burned” for my transgression.


The stung area throbbed slightly, occasionally shooting out small spikes of pain to remind you it was there. Blisters looked like they were forming, but fortunately, did not quite bubble to the surface of the skin. Chay Hoon wasn’t sure what species it was, but muttered something about “not sure if it is the species that has flesh-eating bacteria”! I suppose if my finger drops off in a weeks time, we’ll know for sure!

And there you have it. The essence of a “good” dive! 🙂

Butter … Fly … Fish 25 Aug 2011

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Three everyday words that, when put together, describe a very colourful fish, that is one of the key indicators of coral reef health. The logic behind it being a key indicator is the fact that most butterflyfish are either solely or partially dependent on corals as a source of food. Therefore, if the butterflyfish population in “healthy” or abundant, it means the reef is doing well also. Of course this does not mean that ALL butterfly fish can be used that way, since some of them do not feed on corals at all.

Anyways, I’ve spotted two new species of butterfly fish in Singapore over the last 3 years, and, similar to my post on anemonefishes, I thought it would be a good idea to continue writing about the common fish species on our reefs.

Presenting …… THE BUTTERFLYFISHES OF SINGAPORE! They are (in alphabetical order):

1. Chaetodon octofasciatus (Eight band / Eight-banded Butterflyfish)
Probably the most common butterflyfish in Singapore, they can be found on all our reefs, either alone or up to groups of 4. Juveniles tend to hide between the branches of coral (such as Acropora or Pocillopora) to avoid their enemies. They feed on corals (Allen, 1985).

2. Chaetodon adiergastos (Panda Butterflyfish)
This fish is a possible new record for Singapore, and was sighted at Kusu Island. IUCN lists Singapore as one of the countries that this fish occurs in, but does not mention the source of this information. Allen (1985) and Fishbase do not list Singapore as a site that this fish occurs in.

3. Chelmon rostratus (Copperband / Copperbanded Butterflyfish)
Photo by Eunice Khoo
The second most common butterflyfish on our reefs, this species has a fairly long snout, which it uses to good effect, snatching up crabs, worms and other invertebrates (Allen, 1985). Usually travels in pairs.

4. Coradion chrysozonus (Goldengirdled / Orangebanded Butterflyfish)
This fish is quite rare, and has been observed at Semakau and the St John’s group of islands. Lieske & Meyers (1994) say they feed on sponges, but Allen (1985) states that it has an omnivorous diet.

Heniochus varius (Horned / Humphead Bannerfish)
Only one sighting of this fish has been reported for Singapore so far (Low et al, 2009). They are thought to feed on corals and other invertebrates (Lieski and Meyers, 1994).

Parachaetodon ocellatus (Sixspined / Ocellate Butterflyfish)
Kite butterflyfish
Photo by Debby Ng
Another rarely seen fish, this species is usually seen in areas with seagrass beds (eg. Semakau). Is thought to be an omnivore (Allen, 1985).

A fish that is often mistaken for a butterflyfish is the Vermiculated Angelfish (Chaetodontoplus mesoleucus). It is a smallish and colorful angelfish, but has a spine on the operculum (a characteristic feature in angelfishes, but not found on butterflyfishes).
Photo by Khoo Minsheng


Allen, GR, 1985. Butterfly and angelfishes of the world. Vol 2. 352pp Mergus Publications, Germany.

Lieske, E and R Myers, 1994. Collins Pocket Guide. Coral reef fishes. Indo-Pacific & Caribbean including the Red Sea. Haper Collins Publishers, 400 p.

Low, JKY, JIT Tanzil & Z Jaafar, 2009. Some note-worthy fishes observed in the Singapore Straits. Nature in Singapore, 2: 77–82. [PDF, 554 KB]

On-line resources:


Nature in Singapore

New record of butterflyfish? 16 Aug 2011

Posted by cat64fish in Tales from the N2 bar.

While doing a fish survey at Kusu Island (on 14 Aug 2011), I came across this butterflyfish, which I have not seen before in Singapore. Thanks to my trusty Canon S95, I manged to snap off a few shots and came up with three very clear images of the fish.




It is Chaetodon adiergastos, or the Panda Butterflyfish.

IUCN lists Singapore as one of the countries that this fish occurs in, but makes no mention of the reference. Fishbase on the other hand, does not. Either way, I’ve not seen this butterflyfish before at any of the sites we survey, so it is very exciting!!