Angelfish are some of the most vibrant creatures on the reef, but there's a lot more to these angelic fish than first meets the eye. From the fascinating ways they communicate to their captivating personalities and even their preferred cuisine, read on to discover our top ten angelfish facts...
A diverse family
Let's kickstart our list of cool angelfish facts, by exploring how they got their name. It's thought that the name 'angelfish' is related to appearance, with their triangular body shape and long flowing fins reminiscent of angel wings. Angelfish belong to the cichlidae family, which includes over 90 species in freshwater and marine environments. One type of angelfish is the marine angelfish, renowned for their vibrant colours. Some popular species include the emperor angelfish, commonly sighted in the Red Sea, the Maldives and Indonesia, and the dazzling queen angelfish, found in the Gulf of Mexico and the Bahamas.
Angelfish or butterflyfish?
Angelfish and butterflyfish are closely related, making it tricky to tell them apart since they share similar appearances and behaviours. When you're swimming along a coral reef and don't have your trusty fish identification book to hand, the trick for telling them apart lies in their shape. Angelfish have a more triangular appearance, with dorsal fins that extend dramatically, giving them a sharper and more angular outline, which helps them move through dense vegetation. In contrast, butterflyfish have a softer, rounded shape with a less pronounced profile. You can also tell them apart by their personalities; angelfish have a slight attitude problem, whereas butterfly fish are known for their peaceful demeanour.
Communication
Another intriguing fact about angelfish is how they use sound to communicate. They do this by emitting low-frequency clicks and grunts, most commonly during territorial disputes to assert dominance or when finding a mate. They make these unusual sounds by grinding their teeth and using specialised muscles around their jaws. In addition to vocal communication, they use body language - such as fin displays and postures - to convey aggression, attraction or submission.
Colour variations
Angelfish are known for their stunning array of colours and patterns. However, they're not just for show; they use their eye-catching colours for mating displays and to help them blend into the vibrant coral reefs. One of our favourite types of angelfish is the emperor angelfish (found around the Red Sea and the Maldives). Juveniles are adorned with blue and yellow circular patterns, while matured adults have deep blue, yellow and black colourings and bold angular stripes. We also love the aptly named flame angelfish (commonly found in French Polynesia and Fiji) which displays a fiery orange-red colour; the coral beauty angelfish (often seen in the Philippines and Indonesia) which boasts a mix of purple, blue and orange markings; and finally, the queen angelfish which shimmers through the waters of the Bahamas and the Gulf of Mexico in blues and yellows.
Territorial behaviour
Don't be fooled by their angelic appearance; angelfish can be pretty territorial. They claim sections of the reef or specific coral formations as their homes, which they will protect from intruders. Angelfish seek shelter on coral reefs - hiding in small crevices, caves and overhangs to protect themselves from predators - and juveniles, in particular, are masters of finding small hidden spaces. Hierarchy also plays a significant role in the territorial behaviours of angelfish, with larger individuals often controlling more extensive areas, while smaller fish and juveniles occupy more modest and less protected spaces. During mating season, nesting sites become fiercely defended by a pair of angelfish who will assert their dominance and warn off potential threats.
Breeding and parenting
After an angelfish finds a mate, they begin a fascinating courtship ritual involving synchronised swimming, fin displays and mutual cleaning; this helps reinforce their bond, which is crucial as angelfish form strong, lifelong bonds. Once a pair is established, they will work together to breed and raise their offspring, with the female first laying her eggs on a flat surface such as a rock or coral formation while the male fertilises them. They will both take turns to guard the eggs and fan them, a rare behaviour that prevents fungus growth and ensures proper oxygen flow. After hatching, the parents will continue to protect their young while they grow up and become independent.
Symbiotic relationships
Our favourite angelfish fact is that they engage in fascinating symbiotic relationships with other sea creatures. Juvenile angelfish, such as the bluedisk angelfish, often play the role of the underwater cleaning crew. They remove parasites, dead skin and bacteria from larger fish species like groupers, barracudas and even sharks. But this isn't just a spa day; it also benefits both species, with the angelfish enjoying a meal while the larger fish are relieved of potentially harmful parasites. And it's vital for maintaining the overall health of the reef ecosystem. These cleaner fish also have specialised behaviour to attract hosts, often performing a cleaning dance to signal their intent.
Extraordinary vision
If you thought X-ray vision was incredible, then wait until you hear that angelfish have UV vision! This allows them to see a broader range of colours than humans, including ultraviolet light, an adaptation that is crucial for their survival, helping them to locate food and easily navigate through their habitat. While humans can't naturally see this ultraviolet light, we can experience the reef through an angelfish's eyes through UV diving, which uses special filters and lights to reveal hidden patterns and vibrant colours.
A diverse diet
Angelfish are true foodies with a diverse diet. Their meals mainly consist of sponges, algae and plankton found near to their reef habitat. But they're not picky eaters, and depending on their environment, they may also consume small invertebrates, detritus and even bits of coral. This broad diet allows them to graze on different parts of the reef and helps them maintain the energy needed for their vibrant displays and active lifestyles.
Extreme habitats
Our final angelfish fact is about the range of environments they can be found in. Angelfish are remarkably adaptable; some species thrive in warm tropical waters, and others can live in extreme habitats. The regal angelfish can be found in the warm, crystal-clear waters of the Indo-Pacific region, including the Maldives and Indonesia, feeding on sponges and algae on the colourful coral reefs. On the other end of the spectrum is the freshwater angelfish, which can be found in the brackish waters of the Amazon River basin, where they can tolerate fluctuating salinity and oxygen levels.
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