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It had already been a wonderful dive when I suddenly spotted a group of small yellow fish a few metres away. Always on the lookout for rare and unusual fish, I got very excited when I realised the small yellow fish were Herald’s Angelfish. I slowly creeped forward, hoping the fish would stay in the open. Unfortunately, before I could get within camera range the shy fish disappeared into a crevice. I decided to wait and see if they would reappear, and today was my lucky day, as one fish emerged and posed perfectly for my camera and then vanished again. I couldn’t have been happier, as after forty years I had finally photographed a Herald’s Angelfish, a member of a very elusive club – the pygmy angelfish!

Angelfish are some of the most colourful and beautiful of all the reef fishes. The larger members of this family are well-known to divers, as they are regularly spotted swimming over reefs. However, the smaller members of the family, which are known as pygmy angelfish, are shy and cryptic, and very quick to hide when a diver gets too close. I have had a soft spot for pygmy angelfish for many years and I am always on the lookout to capture images of these elusive fish.

The angelfish family, Pomacanthidae, contains 88 species that are found in tropical and subtropical waters around the planet. Sometimes confused with butterflyfish (and damselfish in the case of some pygmy angelfishes), angelfish have several different body characteristics, with the easiest way to tell them apart being the prominent spine on the operculum (gill cover) of angelfish. Most angelfish observed on coral reefs range from 25cm to 50cm in length. However, around half the known species are less than 15cm long, and these are the pygmy angelfish.

PYGMY ANGELFISH

Most pygmy angelfish are members of the genus Centropyge. In this group are 35 related species that are quite small, ranging in size from 6cm to 18cm long. These small fish are benthic omnivores, feeding on either algae or small invertebrates, or both. Pygmy angelfish are usually shy and found on reefs with plenty of cracks and crevices. They never venture too far from one of these hiding spots and flee if a diver or predator swims by.

Pygmy angelfish are found in small groups (unlike most large angelfish that are seen in male/female pairs), which is usually a male and up to seven females. The males and females have the same colour pattern, so look identical, yet the females are often smaller with more rounded fins. The male is the dominate member of the group and fiercely guards his territory from other males. While the females have their own pecking order, determined by their size.

When it comes time to reproduce, each female establishes her own little patch, and when the male comes for a visit (usually around dusk), she releases her eggs for him to fertilise. Pygmy angelfish are pelagic spawners, with the eggs drifting with ocean currents. After the young hatch, they continue to drift for weeks until they establish on a new reef. Young pygmy angelfish have the same colour patterns as their parents, unlike the young of large angelfish that have different colours patterns until they reach adulthood.  

Angelfish are protogynous hermaphrodites, meaning they are born female and can change sex to become male. This only happens when the male dies, then the dominate female changes sex to take his place. This process takes around 20 days.

It is thought that most pygmy angelfish live for five to seven years. These lovely little fish are found on coral reefs and rocky reefs, in lagoons and on deep drop-offs. They are most numerous and abundant in the Indo-Pacific region, with a few species also seen in the western Atlantic Ocean. However, they are absent from the eastern Pacific and eastern Atlantic Oceans.

The more conspicuous species are seen flitting around on shallow reefs, but many shy and elusive species hide in caves and crevices and are rarely seen. Over the last few decades, several new pygmy angelfish species have also been discovered in the twilight zone, in depths between 60m and 150m, and living in this realm they are only observed by tech divers.

IMAGE BELOW - BICOLOR ANGELFISH

COMMON PYGMY ANGELFISH

As shy and elusive as most pygmy angelfish are, there are several species that are common and easy to find. One of the most abundant and wide-ranging pygmies is the Bicolor Angelfish (Centropyge bicolor). This species is very conspicuous on coral reefs of the Indo-West Pacific, being half yellow and half blue. The Bicolor Angelfish grows to 15cm long, and family groups are found on coral reefs in depths from 1m to 25m. The males are quite territorial and drive away other males from their territory, which is around 200sqm. However, they appear to tolerate other fishes, including other pygmy angelfish species, sharing their territory.

IMAGE BELOW - KEYHOLE ANGELFISH

Found over the same area, and often sharing territory with the Bicolor Angelfish is the Keyhole Angelfish (Centropyge tibicen). This species is a dark blue to black colour with a white keyhole pattern on its side and grows to 19cm long. With its darker colour pattern, the Keyhole Angelfish is less obvious on coral reefs where they are found in depths from 4m to 35m.

The Coral Beauty Angelfish (Centropyge bispinosa) is one of the most wide-ranging members of the family, found from East Africa to French Polynesia. This species grows to 10cm long and is a bright blue colour with orange on its side. However, the intensity and shape of this pattern varies from location to location. Coral Beauty Angelfish are found in a variety of reef habitats between depths of 5m and 50m.

The Pearlscale Angelfish (Centropyge vrolikii) is another common and wide-ranging species found throughout the Indo-West Pacific region, but it is far more cryptic than the previous species. This fish is a pale grey colour with the back half of its body black. It grows to 12cm long and is found on coral reefs and reef walls in depths from 1m to 25m.

I have had numerous encounters with all of the above pygmy angelfish species. They are seen on the subtropical reefs off my hometown of Brisbane, Australia, but I have also encountered them on trips to the Great Barrier Reef and other destinations throughout the Indo-Pacific region.

IMAGE BELOW - CORAL BEAUTY ANGELFISH (LEFT) AND PEARLSCALE ANGELFISH (RIGHT)

RARER PYGMY ANGELFISH

Most pygmy angelfish are rarely seen, as they are shy and elusive and like to hide in caves, cracks and crevices. To find them takes time, patience and being in the right spot at the right time. The following species are some of the rarer pygmies I have encountered; they might not all be rare, nevertheless they are all hard to find and photograph.

There are several uncommon, yellow-coloured pygmy angelfish that are easily confused. The first is the lovely Lemonpeel Angelfish (Centropyge flavissima), which is bright yellow with a light blue ring around the eye and blue highlights on the gill and fins. Growing to 14cm long, this pretty fish is found across a wide area of the Pacific Ocean. The Lemonpeel Angelfish is a shy and elusive species found on coral reefs in depths to 25m. I have seen this species a few times off Brisbane, however Fiji is one of the best places to encounter one.

‍IMAGE BELOW - LEMONPEEL ANGELFISH

Herald’s Angelfish (Centropyge heraldi) is found in the same areas as the Lemonpeel Angelfish, but is a harder species to find and observe. It is also a bright yellow colour, with a dark grey eye-patch and with faint orange markings on the head. Herald’s Angelfish grow to 12cm long and are mostly seen on deeper reefs and walls in depths between 8m and 45m. It took me many years to photograph this species, finally encountering one off Brisbane. I have since found them at Palau and Philippines.

Another yellow-coloured pygmy is Woodhead's Angelfish (Centropyge woodheadi). This is a little-known species from the Western-South Pacific, with its full range still not clear. However, it has been seen off Fiji, Vanuatu and Tonga. Woodhead’s Angelfish grow to 12cm long and has a yellow body and a black dash along the rear of the dorsal fin, highlighted with a blue trim. This species also has a grey eye patch like the Herald’s Angelfish. I have only seen this species in Tonga, and unfortunately had a wide-angle lens on at the time so couldn’t get close for photos of this shy fish.

IMAGE BELOW - HERALD'S ANGELFISH (LEFT) AND WOODHEAD'S ANGELFISH (RIGHT).

The Midnight Angelfish (Centropyge nox) is probably a common species, but it is easily overlooked due to its all-black colouration, its cryptic nature and for the fact that it looks more like a damselfish than an angelfish. This species grows to 10cm long and inhabits coral reefs and walls in depths from 10m to 70m in the western Pacific. I have encountered Midnight Angelfish in the Philippines and Palau, and they are a very difficult fish to observe and photograph.

Eibl's Angelfish (Centropyge eibli) is a species only found in the eastern Indian Ocean. This pretty angelfish is a light yellowish grey with a black tail and orange stripes. This species grows to 15cm long and is found on coral reefs in depths between 3m and 25m. The Eibl’s Angelfish appears to be rare in most locations, but locally common in other areas. I have looked for this fish at several destinations in the Indian Ocean, and finally found one at Christmas Island, and more recently found a few at the Similan Islands, Thailand.

IMAGE BELOW - MIDNIGHT ANGELFISH (LEFT) AND EIBL'S ANGELFISH (RIGHT)

A wide-ranging pygmy seen across the Indian Ocean is the Brown Angelfish (Centropyge multispinis). This species is dark brown with black stripes and blue margins on its pectoral and anal fins. It grows to 14cm long and is found on a variety of reef habitats in depths from 1m to 30m. The Brown Angelfish, with its plain colours, is an easily overlooked species that I failed to find in the Maldives or Red Sea. Fortunately, I recently photograph quite a few at the Similan Islands, Thailand.

The Flame Angelfish (Centropyge loriculus) is one of the prettiest members of this family, and though found over a wide stretch of the Pacific Ocean, appears to be only locally common at a few sites. Bright orange in colour, with black bars and blue tips on its dorsal and anal fins, it is a hard fish to miss. This species grows to 15cm long and appears to like the tops of current swept reefs in depths to 20m. I recently encountered twelve Flame Angelfish on one exposed reef at Palau, yet at all the other reefs I explored I only found one more of these pretty fish.

IMAGE BELOW - BROWN ANGELFISH (LEFT) AND FLAME ANGELFISH (RIGHT).

A very rare member of this family that likes to live in caves is the Cocos-Keeling Angelfish (Centropyge colini). This gorgeous little fish grows to 9cm long and is a pale-yellow colour with a blue back. Found across the Indo-West Pacific, this small angelfish is only occasionally seen, as it is shy and hidden in dark recesses in depths between 20m and 100m. On a recent trip to Palau, I found four Cocos-Keeling Angelfish on two dives in large dark caves. The fish were extremely shy and very reluctant to have their photo taken.

IMAGE BELOW - COCOS-KEELING ANGELFISH (LEFT) AND COCOPEEL ANGELFISH (RIGHT)

While this species is sometimes seen at the Cocos-Keeling Islands, these islands and nearby Christmas Island, also have several endemic pygmy angelfish species. When diving these Australian Indian Ocean Territories, I managed to photograph the Cocopeel Angelfish (Centropyge cocosensis), which looks very similar to the Lemonpeel Angelfish, and the Yellowhead Angelfish (Centropyge joculator), which looks like a cross between this and the Bicolor Angelfish.

‍IMAGE BELOW - YELLOWHEAD ANGELFISH

Another rare pygmy angelfish is the Barred Angelfish (Paracentropyge multifasciatus). This pretty fish is in a different genus to all other pygmy angelfish and looks more like a butterflyfish. Found in the Western Pacific, this lovely fish is white with black bands and a yellow trim to its belly and lower fins. The Barred Angelfish grows to 12cm long, and it appears to have a similar social life to other pygmy angelfish, with a male having a small harem of females, with both sexes looking similar. These pretty fish are very secretive and generally found hiding in caves and ledges on reef walls in depths between 10m and 70m. I have encountered this species in Papua New Guinea, Palau and the northern Great Barrier Reef.

IMAGE BELOW - BARRED ANGELFISH

HYBRID PYGMY ANGELFISH

It is quite common to see several different pygmy angelfish species milling together on a reef, sharing the same cracks and crevices. Some of these angelfish are so friendly that they interbreed to produce hybrids.

Quite a number of pygmy angelfish seem to like mixing the gene-pool, unfortunately the only one I have seen a few times on my local reefs off Brisbane is the Lemonpeel Pearlscale Hybrid Angelfish (Centropyge flavissima × vrolikii). This species has a colour pattern that is a blend of its two contributing parents and on some reefs this hybrid is more common than its parent species.

Why pygmy angelfish interbreed is unknown, though it could be a result of a small population of some species. However, a recent study by Yi-Kai (Kai) Tea, PhD candidate at the University of Sydney’s School of Life and Environmental Sciences, Professors Nathan Lo and Simon Ho, Dr Joseph DiBattista from the Australian Museum, Jean-Paul Hobbs from the University of Queensland, and Federico Vitelli from Edith Cowan University, found that angelfish in general produce more hybrids than any other family of reef fishes, with 42 species known to interbreed.

The study found that some angelfish species managed to interbreed with a 12% difference in their mitochondrial DNA. The researchers found this astounding, as the genetic separation between species to typically produce hybrids is usually only 2%. They also found that hybridization concurred almost anywhere different angelfish species exist side-by-side, while in other reef fish families, hybrids only occurred when similar species closely share habitats.

IMAGE BELOW - LEMONPEEL PEARLSCALE HYBRID ANGELFISH

PYGMY ANGELFISH MIMICS

There are several fish species that mimic other fish to keep them safe from predators. Almost all of these mimics copy the colour patterns of venomous fishes to fool predators into thinking they are also venomous. However, for some strange reason several species of surgeonfish, when juveniles, have copied the shape and colour pattern of pygmy angelfish.

In the Pacific Ocean, the Pacific Mimic Surgeonfish (Acanthurus pyroferus) has a colour pattern identical to the Lemonpeel Angelfish or the Pearlscale Angelfish, depending on the location. While in parts of the Indian Ocean, the Indian Mimic Surgeonfish (Acanthurus tristis) has colour patterns like the Eibl’s Angelfish. These mimics even have a similar body shape and fins and also imitate the swimming style and behaviour of the pygmies, staying close to the reef and darting into cracks and crevices when larger fish are nearby.

The mimics retain these copied colour patterns until their grow larger than the pygmies and develop their defensive blade at the base of their tail. At this stage they also change shape with their tails becoming fork-shaped and their snouts elongating until they start to look like a normal surgeonfish.

Why they have chosen to mimic pygmy angelfish is not fully understood, as pygmy angelfish are non-venomous. However, with their shy and elusive behaviour, it is thought that few fish predate on pygmy angelfish as they are just too difficult to catch (and photograph at times), with the mimic surgeonfish benefiting from this sneaky behaviour.

There are still plenty of pygmy angelfish for me to see and photograph, and I can see many years ahead of me looking into countless cracks and crevices for these beautiful and elusive little fish.

IMAGE BELOW -PACIFIC MIMIC SURGEONFISH LOOKING LIKE A PEARLSCALE ANGELFISH