Rusty Dwarf Angelfish, Rusty Pygmy Angelfish, Rusty AngelFamily: Pomacanthidae Centropyge ferrugataPhoto © Animal-World: Courtesy Hiroyuki Tanaka
The Rusty Angelfish is a great member of the cleanup crew, being a detritus and algae eater, and it comes in a compact size!
The Rusty Angelfish Centropyge ferrugata is a vibrantly colored dwarf angel. The golden orange body is topped with irregularly shaped black dots in a vertical stripped pattern and it has a brilliant neon blue edging to the fins. It's a small sized angel too, not quite reaching 4 inches (10 cm) in length. Despite its flashy coloring this is one of the less aggressive angelfish making it more likely to behave itself in your tank.
It is very similar in appearance to the well known Coral Beauty Centropyge bispinosus and the Shepard's Pygmy Angelfish Centropyge shepard. Like these two, this dwarf Angel stands out as an excellent addition to the home aquarium. Both the Rusty Angel and the Shepard's are distinguished from the Coral Beauty because they are much more orange and they have a lighter coloring on the dorsal, anal, and caudal fins. These two also lack the Coral Beauty's bluish color over the head and on the face. To tell these two apart look at the dark stripped patterning on the body. The Rusty has lines of irregularly shaped black dots across the entire body while the Shephard's has broader stripes, but only on the upper half.
In captivity these dwarf angels are moderately hardy. They do need to be maintained in better water quality than what's required for most saltwater fish, so are suggested for an intermediate aquarist. But they are great little angelfish that are not too picky about what they eat and are great foragers. Their natural diet consists mostly of algae and detritus, which keeps them very active moving around picking at the substrate and the rockwork. They can handle some neglect and they will even breed in captivity. They can be kept in a mature tank over 30 gallons it they are the only fish, but do best with 55 gallons or more. The best environment is one with live rock that can help supply them with plenty of natural algal foods, and positioned to create lots of hiding places.
They do best in a fish only saltwater aquarium as they can become a nuisance in reefs. It is possible to keep them in a reef tank with leather corals and some of the more noxious soft corals, since most don't harm these. But you must keep an eye out for problems as they can turn destructive. They are less suitable to other types of reef tanks as they are harder on corals than other types of angelfish. They may nip at stony coral polyps, sponges, clam mantles, tiny snails, and other invertebrates.
These angelfish are generally not overly aggressive with their tankmates. Like most angelfish, they get along with tankmates best when they are the only type of dwarf angelfish in the aquarium. However it can be housed with other species of dwarfs as long as they are all added at the same time. Be careful to only combine angelfish with very distinct color variations.
When choosing a Rusty Dwarf Angelfish, look for a specimen that is alert and picking at rocks. Its body should be filled out, have no fin or body damage, and it should be brightly colored. A healthy specimen will also show an initial curiosity about who is approaching its tank, then quickly dart into hiding. All Rusty Angelfish are born female. They can be paired according to size by buying one large and one small Rusty Angelfish. Within a few months, they will assume their roles as male and female. Offer plenty of hiding spaces within the rock. In general, dwarf angelfish may spawn in captivity under the right circumstances.
For more Information on keeping saltwater fish see:
Marine Aquarium Basics: Guide to a Healthy Saltwater Aquarium
- Minimum Tank Size: 55 gal (208 L)
- Size of fish - inches: 3.9 inches (10.01 cm)
- Aquarium Hardiness: Moderately hardy
- Temperament: Semi-aggressive
- Temperature: 71.0 to 82.0° F (21.7 to 27.8° C)
- Range ph: 8.0-8.4
- Diet Type: Omnivore
The Rusty Angelfish Centropyge ferrugata was described by Randall and Burgess in 1972. They are endemic to the Western Pacific and are found in Tanabe Bay and from southern Japan to the southwest tip of Taiwan, and in the Philippines. The genus Centropyge currently has over 33 species, and are members of the Pomacanthidae family.
It is on the IUCN Red List as Least Concern (LC) as this dwarf angelfish has a large population and wide distribution. Although they are harvested for the pet industry it does not globally impact the populations and there are no major threats currently identified. Centropyge will spawn in captivity and some are now being raised in captivity, thus helping to preserve our ocean reefs. The common names, Rusty Angelfish, Rusty Dwarf Angelfish, or Rusty Pygmy Angelfish are derived from their rusty coloration.
These dwarf angels are found at depths from 20 - 98 feet (6-30 m). They inhabit seaward reefs that are surrounded by rocky areas which provide cover. The rubble areas close by are a good supply of algal growth. These dwarf angelfish are found alone or in small groups eating benthic algae, weeds, cnidarians, hard corals, coral polyps, sponges, and tunicates.
- Scientific Name: Centropyge ferrugata
- Social Grouping: Varies - They may be found singly or in small groups of one male to 6 females.
- IUCN Red List: LC - Least Concern - Stable population.
The Rusty Angelfish has the typical shape for dwarf angels, having a small elongated oval shape body with rounded fins. These angels can grow up to almost 4" (10 cm) in length. They can live 10 -15 years or more in nature, though in the aquarium they live an average of about 10 years..
The Rusty Angelfish looks very similar to the Coral Beauty, with the exception of color. It has an oval body with irregularly shaped black dots on a golden brownish orange color along the top half of the fish and a brighter orange on the bottom half of the fish. There is bluish edging on the outer edge of the dorsal and anal fins. The dorsal fin and most of the anal fin are dark.
- Size of fish - inches: 3.9 inches (10.01 cm)
- Lifespan: 15 years - They live 15 years or more in the wild. In captivity some have been known to live up to 10 years.
Rusty Dwarf Angelfish are moderate to care for as far as providing correct housing. This is a fish for intermediate aquarists or a very dedicated beginner. They are fairly durable as long as tank parameters are met and good water quality is maintained. They do best in a mature tank over 30 gallons unless they are the only fish, with 55 gallons or more being recommended. The best environment is one with live rock that can help supply the necessary amounts of natural algal foods, and positioned to create lots of hiding places. They also are harder on corals than other Dwarf Angelfish, so are not a good choice for a reef.
- Aquarium Hardiness: Moderately hardy
- Aquarist Experience Level: Intermediate - They are a moderately hardy, but a better water quality needs to be maintained than for most saltwater fish.
The Rusty Angelfish Angel is an omnivore. In the wild their diet consists mostly of algae and detritus. They will also pick on the polyps of any stony coral and most soft corals, as well as tunicates, clam mantles, cnidarians, sea squirts and sponges.
In captivity a diet a diet rich in vegetable matter is essential, as well as some proteins. It is important that you feed angelfish all kinds of live, frozen, and prepared formula foods. They do well on frozen foods with marine or Spirulina algae, mysid shrimp, shaved shrimp, and other high quality fare. A mature tank with live rock can help supply a good amount of natural algae foods (containing copepods and other small edibles) and diatom algae. There are several good commercial foods available including Formula II and Angel Formula.
Feed several times a day even if natural foods are present. Unlike other Centropyge, who will stay away from noxious soft corals, the Rusty Angels seem to eat more than their fair share of corals. Keeping them well fed in a reef may discourage them from eating corals, but that is a risk.
- Diet Type: Omnivore - May get most of their veggies from the algal crops on the live rock. Otherwise provide a spirulina type diet. Also needs supplemented meaty foods if the copepod population in the algae is not strong.
- Flake Food: Yes - If they will accept it, offer a food with Spirulina algae and sponge material included.
- Tablet Pellet: Yes - Offer a food with Spirulina algae and sponge material included.
- Live foods (fishes, shrimps, worms): Some of Diet - Brine shrimp, mysis shrimp, as well as other protein sources can be offered occasionally.
- Vegetable Food: Most of Diet - May get most of their vegetable from algae present in tank, but it is also recommended to provide supplemental feedings of a spirulina type diet.
- Meaty Food: Some of Diet - They will eat the copepods found in the algal growth, but there may not be a strong population. It is recommended to also provide a protein type as part of their diet.
- Feeding Frequency: Several feedings per day - This depends on the size of the tank. Feed them 2 to 3 times a day, less in a tank with a lot of natural algae sources. A larger tank of 75 gallons with more algae to forage from, then feed once to twice a day.
The Rusty Angelfish is not as touchy as some of the other species of angelfish, but still needs good water. If they are being kept with live rock, water changes should be performed more often due to the need for clean water conditions with lower nitrates. Water changes of 30% a month, 20% every 2 weeks, or 5% a week is optimal in keeping nitrates lower. Keep pH at 8.0 minimum.
- Water Changes: Bi-weekly - A bi-weekly water change of 10% to 15% is suggested.for tanks under 75 gallons, and for larger tanks a 20% change every 3 weeks to a month.
A mature tank that is at least 6 months old is recommended for a Rusty Angelfish. A minimum 55 gallons without other algae eating fish to compete with is ideal for its health. Provide Water parameters of: 71-82° F, pH 8.0-8.4, sg 1.023-1.026. For a male and female pair, a tank that is 75 to 100 gallons provides more food and cleaner water. Housing them in a tank smaller than 55 gallons is not suggested as they will have less natural foods for this constant grazer. Also with frequent feedings the bio-load is larger, which can cause the water to foul quickly. Smaller tanks can also invite a territorial and aggressive behavior toward other fish and stress, which can lead to crypt and other illnesses.
It is best to introduce the Rusty Angelfish last. and as a young fish into an established tank with plenty of algae growth. Like all dwarf angelfish, they like to have lots of rubble type areas to pick natural foods from and larger rock work to hide in to feel secure. A 55 gallon tank can use about 80 lbs. of live rock. (1.5 to 2 lbs per gallon) for a good algae growth.
- Minimum Tank Size: 55 gal (208 L) - A 55 gallon tank is the suggested minimum but closer to 75 gallons is best, and 100 gallons is needed for a male/female pair. A larger aquarium can provide enough algae on live rock to sustain the dwarf angelfish through a natural diet, and keep it healthy. Smaller tanks can also cause aggression.
- Suitable for Nano Tank: No - Not even as a juvenile.
- Live Rock Requirement: Typical Plus Hiding Places - They are hunted in the wild, so the need to hide is very strong for this fish, and a good amount of live rock will supply natural algae for it to feed on.
- Substrate Type: Any - They do appreciate areas of rubble rock with algae growth to feed from.
- Lighting Needs: Any - ighting should be strong enough to support algae growth. If tank has low lighting, making sure direct sunlight hits the tank to support this natural food is suggested.
- Temperature: 71.0 to 82.0° F (21.7 to 27.8° C)
- Breeding Temperature: 77.0° F - At a temperature of 77° F hatching is 16 hours after spawning. Longer if water is cooler.
- Specific gravity: 1.023-1.026 SG - They do not do well long term with a pH below 1.023 as it can cause liver damage. All angelfish are sensitive to low salinity treatments, so try to minimize anything below 1.019 for extended periods of time.
- Range ph: 8.0-8.4 - Angelfish will deteriorate quickly below 8.0 and it will cause health problems.
- Brackish: No
- Water Movement: Any - They like areas of swift movement as well as areas of slower movement.
- Water Region: Middle - They will also inhabit lower areas of the tank.
Although still considered semi-aggressive, the Rusty Angelfish is actually one of the least aggressive Dwarf Angelfish. However, if housed in a smaller tank they will become aggressive as with all Centropyge. Competing with other algae eaters can also cause them to "not play well with others". A much larger tank would facilitate other algae eaters, such as a tank with a longer footprint close to 6 feet.
As with most fish, two males will fight to the death. Rusty Dwarf Angelfish do not get along with other dwarf angels unless the tank is well over 100 gallons and there are plenty of hiding places for both and plenty to eat. Making 2 separate "reefs" in a longer tank helps to "divide the line" thus the above mentioned 6? long tank. However a pair, male and female can work in a 75 to 100 gallon tank. The Rusty Angelfish will pick at SPS, LPS, clams, and anemones. They will even pick at some soft corals, unlike some other 'reef-safe' Centropyge.
- Venomous: No
- Temperament: Semi-aggressive - This fish is best kept as the only dwarf angelfish in the marine aquarium unless tank is well over 100 gallons.
- Compatible with:
- Same species - conspecifics: Sometimes - A male/female pair will work in a 75 gallon as will two of the same sex. Different species that do not look similar can be kept in tanks over 100 gallons.
- Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Monitor - In smaller tanks under 55 gallons, they may harass peaceful smaller fish.
- Semi-Aggressive (anthias, clownfish, dwarf angels): Safe
- Aggressive (dottybacks, 6-line & 8-line wrasse, damselfish): Monitor - Some of the more aggressive fish can cause them to not emerge or eat. Make sure the angelfish is not hiding and comes out to feed.
- Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor - Can be kept in tanks over 75 gallons as long as the dwarf angelfish is coming out and eating, and is not being harassed.
- Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat - Dwarf Angelfish will be eaten by large fish that can fit them into their mouths.
- Slow Swimmers & Eaters (seahorses, pipefish, mandarins): Threat - Dwarf Angelfish will out compete slow eaters, possibly leading to the tankmates starvation.
- Anemones: Monitor - May be safe if the anemone has a clownfish or a pair of clowns to protect it.
- Mushroom Anemones - Corallimorphs: Monitor - May eat waste exuding from mushrooms, which is not harmful, just keep an eye on the fish.
- LPS corals: Monitor - May eat slime layer, causing coral to close and eventually die. In a very large system, the damage may not be as severe.
- SPS corals: Monitor - May eat slime layer, causing coral to close and eventually die. In a very large system, the damage may not be as severe.
- Gorgonians, Sea Fans: Threat - The dwarf angel may nip at its appendages, those "feather-like" polyps that protrude. This is often because Gorgonians can quickly be covered by algae, which may be what the angelfish is most interested in picking at.
- Leather Corals: Safe
- Soft Corals (xenias, tree corals): Monitor - May pick at appendages. Safe with most from the Effatounaria genus, but still monitor for individual preferences.
- Star Polyps, Organ Pipe Coral: Monitor - May nip at polyps if not well fed.
- Zoanthids - Button Polyps, Sea Mats: Monitor - May nip at polyps if not well fed.
- Sponges, Tunicates: Monitor
- Shrimps, Crabs, Snails: Safe
- Starfish: Safe
- Feather Dusters, Bristle Worms, Flatworms: Monitor - May pick at appendages.
- Clams, Scallops, Oysters: Monitor - May pick at the mantles of clams. Most angelfish eat the slime layer of clams, causing them to close and eventually die.
- Copepods, Amphipods, Mini Brittle Stars: Safe - Will not decimate populations as it is not a obligate eater of these foods.
All Centropyge are born as female, and as they grow within their social structure, the larger and more dominant fish will become male, while the remaining fish stay female.
The Rusty Angelfish has been reared in captivity, but not bred in captivity as of yet. Dwarf angelfish are broadcast spawners, releasing eggs and sperm simultaneously at dusk, a week before the full moon. They start mid-December and continue through May, at which time they will rise into the water column and release eggs and sperm simultaneously near the surface.
The eggs will hatch in just under a day, about 16 hours for water that is 77 to 79 F, then within 2 to 3 days they need microscopic algae for their very small mouths. This is where raising any dwarf angelfish becomes difficult.
- Ease of Breeding: Difficult - Very small plank-tonic foods are needed when rearing the larvae, as they have very small mouths.
Providing a dwarf angelfish with plenty of places to hide and clean water is the best way to prevent illness. Calm fish are healthy fish. If not stressed, they will have a stronger immune system to prevent infections. Like other saltwater angelfish, dwarf angelfish can suffer any disease that captive saltwater environments have to offer. Fish problems can be broken into one of (or a combination of) these types: parasites, bacterial and fungal disease, or physical ailments (wounds and injuries). To learn all about fish problems and find specific answers, see Aquarium Fish Diseases and Treatments.
The best and first defense to prevent diseases is a quarantine period before introducing a new fish. Quarantine tanks should be bare with a PVC tube where the fish can hide. Do regular water changes every day or so. Secondly, fresh water dips can also help to kill anything that is on their body that may spread. PH and temperature must be the same (just use baking soda to bring up the PH if you have soft water but use a test). Start with 5 minutes and up to 15 minutes if they are not showing any signs of distress. This is really only needed if you see anything on their body or if the back fin is starting to fray.
Dwarf angelfish diseases and treatments:
- Parasitic and Protozoan diseases
Dwarf angelfish are prone to parasites like White Spot Disease Cryptocaryon irritans, also known as Marine Ich, Saltwater Ich, or Crypt. Another common disease is Marine Velvet or Velvet Disease Oodinium ocellatum, (syn: Amyloodinium ocellatum or Branchiophilus maris), which is a parasitic skin flagellate. These are two of the most common diseases.
- Symptoms of White Spot Disease are constant scratching and flashing, culminating with numerous white dots all over the body and fins. These dots disappear for a few days, only to return with double the number. This results in the fish suffocating from these parasites blocking the gills from providing oxygen.
- Symptoms of Marine Velvet are a peppery coating giving a yellow to light brown "dust" on body, clamped fins, respiratory distress (breathing hard as seen as frequent or quick gill movements), cloudiness of eyes, glancing off decor or substrate, and possible weight loss.
- Treatment of parasites
For external parasites you can slowly increasing the temperature of your tank to at least 82° F (28° C). That will prevent the parasite from completing its life cycle which includes the attachment to fish. A further combination of the higher temperatures with medicated food will provide timely relief.
Parasites on marine fish kept with live rock or in any type of reef environment can be extremely difficult to treat. Typical treatments like copper and formalin solutions, as well as quinine based drugs are harmful to other marine creatures. However drugs such as metronidazole provide an effective and safe treatment for several protozoan and anaerobic bacterial diseases.
Metronidazole works by ceasing the growth of bacteria and protozoa. Metronidazole is an antibiotic for anaerobic bacteria with anti-protozoal properties. This drug is reef safe, and medications are either added to the water or mixed with the fish food. Some available products that contain metronidazole include Seachem Metronidazole, Seachem AquaZole, Thomas Laboratories' Fish Zole and National Fish Pharmaceutical's Metro-Pro.
The Seachem Metronidazole medications works well in combination with another Seachem product called Focus, which is a bonding agent. This treatment can be used in a reef aquarium since the medication is bound to the food, which even if the corals eat, will not hurt them. Mix Focus in a ratio of 5 to 1 with their Metronidazole (5 parts Focus to one part Metro), then mix this with 1 tablespoon of food. Feed the medicated food to the fish 3 times a day for at least a week or until symptoms are gone.
- Treatment of parasites
- Bacterial Diseases
As with all dwarf angels, they are also vulnerable to bacterial and fungal diseases. Bacterial infections are often a secondary infection resulting from damage caused by a parasitic or protozoan disease. One of concern is the Vibrio bacteria, which starts as an internal infection, turns into Dropsy, Popeye, Bleeding or Red Streaks on the skin. It is a very fast acting bacteria that will kill your angelfish in days. One way it typically starts is with an innocently frayed back fin. This disease will quickly spread and kill a fish within 2 days.
- Treatment of bacterial diseases
Fresh water dips are an important step to kill anything that is on their body that may spread. PH and temperature must be the same (just use baking soda to bring up the PH if you have soft water but use a test). Start with 5 minutes and up to 15 minutes if they are not showing any signs of distress. This is really only needed if you see anything on their body or if the back fin is starting to fray. Only treat in 1/2 doses any medications containing cleated copper as all angelfish are sensitive to this element in it's free form.
For dropsy, popeye, fin/tail rot and septicemia, which are at time secondary infections, another product you can use along with Seachems Metronidazole or alone is Seachems Kanaplex. You still need to use Focus to bond the Kanaplex to the food. Kanaplex, when used with Metronidazole in the same food, would be 2 scoops of Focus, 1 scoop of Kanaplex and 1 scoop of Metronidazole, yet this combination should only be fed once a day for 7 days, since Kanaplex should only be used for 7 days maximum. If you need to continue past 7 days, use only Metronidazole in a separate mixture for further treatment. This product can also be added to the water (without focus) if the fish is not eating.
- Treatment of bacterial diseases
- Physical Ailments
Physical Ailments are often the result of the environment, either water conditions or incompatible tankmates. Poor quality water conditions can lead to fish gasping, not eating, jumping out of the tank, and more. Dwarf angelfish when very stressed or being picked on will hover in the upper corner of the tank and should be removed if the fish bullying your angelfish is not. Tank mate problems can result in nipped fins and bite wounds..
- Treatment for physical ailments
Look for and remove bully fish.
Products on the market to help include stress relievers like Melafix, Wound Treat, and Bio Bandage.
- Treatment for physical ailments
Rusty Angelfish are moderately easy to find and pricing is in the low to moderate level.
- Animal-World References: Marine and Reef
- Centropyge ferrugata Rusty angelfish, Fishbase
- Centropyge ferrugata, IUNC Red List, International Union for Conservation of Nature and Natural Resources
- Helmut Debelius and Rudie H. Kuiter, World Atlas of Marine Fishes, (in German) Hollywood Import & Export, Inc., 2006
- Scott W. Michael, Angelfishes & Butterflyfishes: Reef Fishes Series , Microcosm Ltd, 2004
- Vincent B. Hargreaves, The Complete Book of the Marine Aquarium, Thunder Bay Press, 2002
- Mark Allen, Roger Steene and Gerald R. Allen, A Guide to Angelfishes and Butterflyfishes , Odyssey Publishing, 1998
- Dr. Gerald R. Allen, Butterfly and Angelfishes of the World Volume 2, Aquarium Systems; 3rd edition,1985