Abudefduf

Abudefduf

The genus Abudefduf comprises a group of well-known reef fish that are often found in tropical and subtropical waters worldwide. These fish are known for their striking vertical stripes, which are often reminiscent of a “sergeant” uniform, hence their popular English name “Sergeant Major Juffers.” Although they live in large schools in nature and feed on plankton, they can become quite territorial in aquariums. They are robust and relatively easy to keep, but their behavior requires attention when setting up an aquarium.

Name and meaning

The genus Abudefduf was first scientifically described in 1775 by the Swedish naturalist Peter Forsskål. He originally described the species Abudefduf saxatilis under the name Chaetodon abudefduf, after which the genus was later established.

The name “Abudefduf” is derived from Arabic. ‘Abu’ means “father of” or “possessor of,” and “defduf” is a local Arabic name for a species of fish, possibly referring to the flat body shape or general presence of these fish. The name can therefore be translated as “father of the side” or “side fish,” which fits well with their laterally flattened body.

The genus Abudefduf belongs to the family Pomacentridae, which also includes reef bass and anemonefish.

Characteristics

Fish from the genus Abudefduf are easily recognizable by their striking appearance and active behavior. Below are the most important characteristics:

• Body shape: They have a laterally flattened, oval body. This makes them agile among rocks and corals.
• Color and patterns: Most species are light-colored (white, silver, or yellow) with distinct vertical black or dark blue stripes across the body. The best-known species, Abudefduf saxatilis (Sergeant Major), has five black stripes and a yellow back.
• Size: Most Abudefduf species grow to between 10 and 20 centimeters in length, depending on the species.
• Fins: They have a sturdy dorsal fin with spines, which protects them from predators.
• Life expectancy: In the wild, they can live for several years; in a well-maintained aquarium, they can sometimes live even longer.

These characteristics make Abudefduf striking and popular fish, both in nature and in the aquarium.

Origin

Abudefduf species are found in tropical and subtropical seas around the world. They are mainly found in:

• Atlantic Ocean: Along the coasts of North and South America, the Caribbean, and West Africa.
• Indian Ocean: Around the east coast of Africa, the Red Sea, the Maldives, and India.
• Pacific Ocean: From East Africa to the islands in the Pacific Ocean, Southeast Asia, Australia, and even as far as Hawaii.

They usually live in shallow coastal waters, near coral reefs, rocky coasts, harbors, and sometimes even shipwrecks. They are often found in the surf, where the water is clear and oxygen-rich. Young fish often stay close to the coast, while adults sometimes venture further out to the reef.

Behavior

Abudefduf species are known for their active and sometimes aggressive behavior, both in the wild and in the aquarium. Below are the most important behavioral characteristics:

• Schooling: In nature, they often live in large schools, especially when they are young. This offers protection from predators and facilitates the search for food.
• Territoriality: Adult fish, especially during the breeding season, can be very territorial. They fiercely defend their nest or favorite spot against intruders, even larger fish.
• Foraging behavior: They are omnivores and actively search for food. They eat plankton, small crustaceans, algae, and sometimes even small fish or eggs of other species.
• Swimming behavior: Abudefduf are fast swimmers and love currents. They are often seen in the upper water layers, where they swim around alertly and curiously.
• Interaction with humans: In tourist areas, they are sometimes so accustomed to snorkelers and divers that they come close, especially when being fed.

In the aquarium, they can be lively and interesting to watch, but their territorial behavior requires careful consideration when selecting other fish to keep with them.

Breeding aquarium and conditioning

Breeding Abudefduf species in an aquarium is possible, but requires a careful approach. Below are the most important points to consider:

Breeding in a regular aquarium or a special breeding aquarium?

• Regular aquarium: In some cases, it is possible to breed Abudefduf in a well-equipped community aquarium, especially if there is sufficient space and hiding places. However, the chances of successful breeding are greater in a special breeding aquarium.
• Special breeding aquarium: For best results, a separate breeding aquarium is often used. This prevents other fish from eating the eggs or larvae and makes it easier to monitor water quality.

Breeding aquarium specifications

• Size: A breeding aquarium of at least 100 to 150 liters is recommended for a pair or a small breeding group.
• Water quality:
  • Temperature: 24-27°C
  • Salinity: 1.023-1.025 SG
  • pH: 8.1-8.4
  • Ammonia and nitrite: 0 mg/l
  • Nitrate: as low as possible, preferably below 20 mg/l
• Lighting: Moderate to bright light, preferably with a day-night rhythm. This mimics natural conditions and stimulates breeding behavior.
• Filter: Use a sponge filter or another soft filter that does not suck up larvae. Good water circulation is important, but avoid too strong a current.

Conditioning the parent fish

• Food: To get the fish in top condition for breeding, feed them a varied diet of frozen food (such as mysis, artemia, and krill), live food (such as water fleas or artemia nauplii), and high-quality dry food. This provides sufficient protein and fat, which is important for egg production.
• Separating males and females: In most cases, males and females are not kept separately, because their presence together actually stimulates mating behavior. Sometimes it can help to separate them briefly and then put them back together again to stimulate breeding behavior.
• Breeding group: If you are breeding with a group, a ratio of one male to two or three females is ideal. This prevents one female from being chased too much and increases the chance of successful breeding.

By following these steps, you increase the chances of successful breeding of Abudefduf species in the aquarium.

Reproduction

The reproduction of Abudefduf species is an interesting and recognizable process that is easy to follow in the aquarium.

• Courtship and pairing: The male chooses a suitable spot on a hard surface, such as a rock or a piece of glass, and cleans it thoroughly. He then tries to attract a female with conspicuous swimming behavior and bright colors.
• Egg laying: The female lays her eggs in the spot chosen by the male. This can be hundreds to thousands, depending on the species and the condition of the female.
• Fertilization and brood care: Immediately after laying, the male fertilizes the eggs. He then guards and cares for the clutch. He ventilates the eggs with his fins to supply them with oxygen and removes unfertilized or moldy eggs.
• Hatching of the larvae: Depending on the temperature, the eggs hatch after 3 to 7 days. The larvae are very small and planktonic; they float in the water and must be fed with very fine live food, such as rotifers or newly hatched artemia nauplii.
• Rearing the young: Rearing the larvae is the most difficult part. They are sensitive to poor water quality and need a constant supply of small, live food. A separate breeding tank with a soft filter and good water values increases their chances of survival.

With patience and the right preparation, it is possible to successfully breed and raise Abudefduf species in the aquarium.

Compatibility

Abudefduf species are striking and active fish, but their compatibility with other aquarium inhabitants requires attention:

• With conspecifics: Young Abudefduf can be kept together in a group. As they get older, they can become territorial and sometimes aggressive, especially during the breeding season. In a spacious aquarium with sufficient hiding places, they usually do well.
• With other fish: They can be kept with other robust, not too shy fish, such as surgeonfish, wrasse, larger cardinalfish, and some angelfish. Avoid keeping them with very calm or small fish, as Abudefduf may chase or intimidate them.
• With invertebrates: They generally leave shrimp, crabs, and snails alone. They are “reef-safe” and do not eat corals, but may sometimes peck at polyps or small invertebrates when hungry.
• During breeding: During the breeding season, males become extra aggressive and actively defend their nest. Other fish may then be chased away from their territory.

Tip: Always provide sufficient space, hiding places, and a good layout of the aquarium to reduce stress and aggression.

Suitable aquariums

Abudefduf species are strong and active fish that can feel at home in various types of saltwater aquariums, provided their basic needs are met.

• Reef aquarium: They are suitable for reef aquariums because they do not eat corals and usually do not harm invertebrates. Their bright colors stand out beautifully among the coral.
• FOWLR aquarium (Fish Only With Live Rock): They also do well in an aquarium without corals but with live rock. Here they can exhibit their natural behavior and there is often more swimming space.
• Aquarium size: Due to their active swimming behavior and sometimes territorial nature, an aquarium of at least 200 liters is recommended, especially if you want to keep several specimens or other active fish.
• Setup: Provide sufficient open swimming space and hiding places, such as rocks, stones, and coral structures. This helps to limit territory formation and stress.
• Water values: Keep the water quality stable and within the correct parameters for saltwater aquariums (see above under care requirements).

Please note: In smaller aquariums, they can become aggressive towards conspecifics or other fish more quickly. A spacious aquarium with a well-thought-out layout is therefore important for their well-being.

Species in the database

Below you will find the species within the genus Abudefduf that we have included in our database: