Bicolor Dottyback (Pictichromis Paccagnellae)

bicolor dottyback - bicolor pseudochromis

Last updated on August 24th, 2022 at 03:48 pm

Bicolor dottybacks (Pictichromis paccagnellae), also known as bicolor pseudochromis, pseudochromis paccagnellae, or just royal dottyback fish, are some of the most beautiful and diverse fish in the aquarium hobby, and popular saltwater fish due to their striking coloration and hardiness in captivity.

Their bright colors, distinctive body patterning, and small size make them ideal additions to almost any tank, whether it’s freshwater or saltwater, coldwater or tropical. They are peaceful, active swimmers that can be kept in large groups or with non-aggressive tankmates of their own species; if cared for properly, they can live long lives and make wonderful pets!

Bicolor dottyback is a type of fish that can be found in the Pacific and Indian oceans, as well as the Red Sea. It’s one of many types of dottybacks (Pictichromis) that have the ability to change color, with their shades varying from blue to purple, depending on their mood and surroundings—and it may help them sneak up on unsuspecting prey items.

Origin and descriptions

bicolor dottyback - bicolor pseudochromis

Commonly known as bicolor dottybacks, pictichromis paccagnellae is a relatively small species of dottyback belonging to the subfamily Pseudochrominae. They are found in shallow reef flats and seaward reefs on most of Australia’s Great Barrier Reef islands, including Lord Howe Island and Middleton Reefs, but also in other areas of New Guinea, around Irian Jaya, Bali and Nias Islands.

These fish grow up to 3 inches long and can be kept singly or in pairs, but not with other dottybacks. The males are more colorful than females, with yellow lines that run along their sides while females have no lines at all.

Species profile

The bicolor dottybacks belong to the family Pseudochromidae. The pictichromis paccagnellae is a marine fish that grows to a size of 3 inches. As its name implies, it has two different colors on its body. They are small, colorful fish that inhabit reefs and lagoons of tropical areas. They are found in marine waters of Indonesia, Philippines, Papua New Guinea, Solomon Islands and Vanuatu.

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Scientific name

The scientific name of the bicolor dottyback is pictichromis paccagnellae.


Pictichromis paccagnellae are from coral reefs in warm waters. They live at a depth of 2-10 meters and can reach lengths of up to 3 inches. Their ideal water temperature is 72 degrees, but they can tolerate temperatures up to 82 degrees for short periods of time. They prefer clean, well-aerated water with minimal nutrients, and are kept in aquariums at a salinity level similar to that of natural seawater.

The tank should have ample places for retreat and plenty of swimming room. The bicolor dottyback does best when kept in groups of five or more individuals. The diet consists mainly of meaty foods such as mysis shrimp, brine shrimp, cyclopeeze, and other frozen meaty foods.


The royal dottyback, or bicolor dottyback, can grow to a maximum size of 3 inches (8 cm) in length.

Tank size

Due to their small size, the minimum recommended tank size is 30 gallons (114 liters) or larger tanks.

Tank requirements

The bicolor dottyback does best in an aquarium of at least 30 gallons. They prefer to have places to hide and are used to swimming in open water, so keep in mind that you will need rockwork or other items for them to hide behind. Like many marine fish, they do best when kept with tank mates of similar size. This fish is not recommended for beginning aquarists because it needs a higher level of care than many beginner-friendly species.

It’s also important to note that these fish can be aggressive toward one another if kept together, so be sure to choose only one if you plan on keeping more than one in your tank.  This fish is not reef safe, as it may eat corals.

The pH range should be between 8.1 and 8.4, and the temperature should stay between 72°F and 82°F; anything outside of that range could cause illness or death in your fish.

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Tank mates

Bicolor dottybacks can be kept with other hardy species, such as clownfish, surgeonfish, and sea turtles. If you’re looking for some colorful companions to keep with your bicolor dottyback, try adding some yellowtail damselfish or a coral goby. Because they are schooling fish, they’ll also enjoy having other fish of their own kind swimming in their tank.


bicolor dottyback - bicolor pseudochromis

The bicolor dottyback can be bred in captivity. In order to induce breeding, males and females should be kept together for a few weeks with no other fish present; provide plenty of live rock rubble for spawning. Fecundity is high and egg counts often exceed 10,000 per gram of female body weight. The incubation period is three days at 82°F (28°C).

Spawning occurs during daylight hours at intervals of 40-50 minutes throughout one day. After spawning, remove eggs from parents as they will consume them. The eggs hatch after some hours and larvae are free-swimming after another few days.

Larvae are planktonic and will feed on copepods, rotifers, nauplii, and flagellates. They should be fed rotifers or newly hatched brine shrimp until they are large enough to accept larger foods such as mysis shrimp or finely chopped seafood diet. Newly hatched brine shrimp nauplii may also be fed to larger larvae if copepods are not available.

Are they aggressive or peaceful?

Bicolor dottybacks aren’t particularly aggressive, but they will defend their territory if needed. They generally get along with other non-aggressive tankmates but may eat small crustaceans such as copepods and amphipods.

Bicolor dottyback care

bicolor dottyback - bicolor pseudochromis

As long as they’re in a large tank with a lot of swimming room, these fish are easy to care for. Feed them small live and frozen foods like mysis shrimp, brine shrimp, chopped-up mussels, copepods, and plankton. These dottybacks aren’t aggressive and don’t need to be housed with larger tank mates.

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Keep several in your home aquarium and watch them interact, grow and eventually spawn! In nature, Pictichromis paccagnellae are found in lagoon and seaward reefs where they feed on zooplankton, algae, and other microorganisms. They prefer rocky or coral-rich areas where there is plenty of nooks and crannies to hide when frightened or when guarding their eggs.

What they eat

Bicolor dottybacks are omnivores, meaning they eat both plant and animal matter. This can include crustaceans, small fish, algae and seaweed. They get most of their food by sifting through sand or corals to find organisms that live on coral reefs. Unlike some types of dottybacks, bicolors do not chase down fast-moving prey but instead wait for slow-moving prey to come near them.


bicolor dottyback - bicolor pseudochromis

Averagely, bicolor dottyback can live for 5-7 years with good care and proper water chemistry.

Parasites and diseases

Pseudochromids, like most fish, are susceptible to parasites and diseases. In order to keep them as healthy as possible, quarantine new arrivals for a few weeks and don’t use live rock from other aquaria. Parasites are another concern for bicolor dottybacks, so be sure your aquarium is well-maintained and clean.

Feed them a diet high in protein and remove any uneaten food from their tank to prevent infestations of hairworms or flukes. If you notice frayed fins or clamped fins, take a sample of water to your local pet store for testing. They may also have an internal parasite infection. These infections require treatment with medications like metronidazole and erythromycin.

Bacterial infections can usually be treated with antibiotics such as Maracyn II, but these drugs must never be used without first consulting with an experienced hobbyist or veterinarian.


Natural enemies of Pictichromis species include wrasses, surgeonfish, triggerfish, and large butterflyfishes. These colorful dottybacks should never be kept with aggressive or territorial fish such as rabbitfish, groupers, or puffers.

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Do they make good pets?

Yes. Bicolor dottybacks are considered to be hardy fish that makes an excellent addition to a saltwater tank. However, they are only recommended for experienced aquarists due to their size and temperament. Because they can reach up to 3 inches in length and have a very boisterous nature, these fish may not be suitable for smaller aquariums and tanks with other shy fish species.

The Bicolor Pseudochromis, or as it is sometimes known, bicolor dottyback, is a peaceful fish. Some people say they are also one of the easiest dottybacks to care for.

The fact that they are so easy to care for has contributed to them being one of aquarium’s most popular species.