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Tono's Dottyback

Pseudochromis tonozukai

Tono's Dottyback is a colorful, aggressive benthic hunter from the Western Pacific. Males display a striking orange stripe. It needs complex cave systems and large tankmates.

Taxonomy
Class:Actinopteri
Order:Perciformes
Family:Pseudochromidae
Subfamily:Pseudochrominae
Genus:Pseudochromis
Species:Pseudochromis tonozukai

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Water Temperature

22 - 27 °C

pH Value

8.1 - 8.4

Water type

Marine

Tank level

Bottom

Adult size

8 cm

Minimum tank volume

>= 120 L

Minimum group

>= 1

Species description

Geographical Origin and Habitat: Pseudochromis tonozukai, commonly known as Tono's Dottyback or Orangeback Dottyback, is native to the Western Pacific Ocean. Its range is highly concentrated in Indonesia (particularly Raja Ampat and the Moluccas) and Palau. It inhabits steep outer reef slopes, deep drop-offs, caves, and crevices at depths ranging from 20 to 50 meters. It is closely associated with rocky substrates where it hovers near shelter, darting into holes at the first sign of danger.
Taxonomy and Morphology: Belonging to the family Pseudochromidae and the genus Pseudochromis, this species features an elongated, slightly compressed body with large eyes and a mouth filled with small, sharp teeth. Its fins are well-developed, with a dorsal fin extending over most of the body length. It is a small species, with adults reaching a maximum total length of approximately 7 to 8 centimeters.
Social Behavior: It is a solitary, highly territorial, and moderately aggressive fish, characteristic of most dottybacks. It establishes a fixed territory around a specific cave or crevice and defends it aggressively against other fish of similar size, especially conspecifics or species with similar coloration. It remains close to its home cave but is active and visible during daylight hours.
Coloration and Sexual Dimorphism: Males exhibit a striking coloration with a bright orange-red stripe running along the back from the snout to the tail, while the lower flanks are pale bluish-grey or white with small vertical dark bars. The eyes feature a brilliant red iris. Females are much more subdued, displaying a uniform greyish-pink coloration. Males will flash brighter colors when courting females or defending territory.

Care, breeding and tankmates

Aquarium Setup: Requires a reef or fish-only aquarium of at least 100 liters. The setup must include extensive live rock work arranged to create numerous caves, tunnels, crevices, and hiding spots. Providing multiple caves allows the dottyback to establish a territory and feel secure, which significantly reduces its overall aggression and stress levels. Keep the tank covered as they are jump risks.
Diet and Feeding: Strictly carnivorous. In the aquarium, they feed on high-quality frozen foods, such as mysis shrimp, brine shrimp, finely chopped krill, and copepods. They will also accept dry pellets and flakes. They are active hunters and will prey on small beneficial micro-crustaceans living on the rocks. Feed once or twice daily in moderate amounts.
Water Quality: Demands stable reef-like parameters: water temperature between 24°C and 27°C, pH between 8.1 and 8.4, specific gravity of 1.020 to 1.025, and carbonate hardness (KH) of 8 to 12 dKH. Keep ammonia and nitrite at zero and nitrates low through regular water changes and efficient protein skimming to ensure long-term health.
Compatibility and Cohabitation: While reef-safe and harmless to corals, it can be highly aggressive towards smaller, peaceful tankmates that occupy the same benthic zone, such as gobies, firefish, and dartfish. It may also prey on small ornamental shrimps. Best kept with larger, active, or semi-aggressive fish like tangs, angelfish, chromis, or larger wrasses. Introduce it as the final addition to the tank.
Aquarium Breeding: Breeding is difficult but possible. They are protogynous hermaphrodites (females can change sex into males). During spawning, the male coaxes the female into his cave where she deposits a ball of adhesive eggs. The male guards and fans the egg mass until hatching. The microscopic fry require live rotifers and copepod nauplii in a separate rearing system.
Risks and Diseases: A very hardy and disease-resistant species. The primary risk is physical injury from territorial fights with tankmates if the aquarium is too small or lacks adequate caves. They can contract marine parasites under extreme stress, but adapt well if quarantined and provided with plenty of rockwork to establish a secure home territory.

Geographic Origin and Distribution

Pseudochromis tonozukai, commonly known as Tono's Dottyback or Orangeback Dottyback, is native to the Western Pacific Ocean. Its range is highly concentrated in Indonesia (particularly Raja Ampat and the Moluccas) and Palau. It inhabits steep outer reef slopes, deep drop-offs, caves, and crevices at depths ranging from 20 to 50 meters. It is closely associated with rocky substrates where it hovers near shelter, darting into holes at the first sign of danger.

Origin

Tropical oceans and reefsSouth and Southeast Asia

Fish profile

Temperament
Territorial
This group is notoriously pugnacious and highly territorial, fiercely dominating their chosen area of the reef structure. They will aggressively and unrelentingly defend their chosen cave or crevice from any perceived intruders, regardless of the intruder's size. Despite their relatively small stature, their bold, fearless, and aggressive nature means they can easily dominate an entire tank if not carefully matched with appropriate tank mates. Impeccable planning of the community dynamic is utterly crucial prior to introducing them.
Diet
Carnivore
They are strictly carnivorous predators, relying on a diet rich in meaty foods in the wild, such as small crustaceans, worms, and zooplankton. In the aquarium setting, they should be offered a highly varied diet including mysis shrimp, enriched brine shrimp, and finely chopped seafood. High-quality marine carnivore pellets or flakes can also be offered as supplementary daily food. Ensuring a diverse and protein-rich diet helps maintain their vibrant coloration and overall immune health.
Sex ratio
Solitary
These species often exhibit distinct sexual dimorphism, with males typically growing larger and displaying much more intense and varied coloration than the females. It is highly recommended to keep them entirely singly or as a carefully matched, confirmed male-female pair. Keeping multiple males or unsexed individuals in the same confined tank almost universally results in severe territorial aggression and inevitable fatalities. Even in very large aquariums, establishing a peaceful pair requires ample physical territory and visual barriers.
Feeding frequency
Twice daily
Due to their highly active nature and carnivorous diet, they should be fed small portions at least two to three times a day. Frequent, smaller meals closely mimic their natural foraging behavior across the reef structure. Avoid feeding large, infrequent meals as this can lead to digestive issues and result in excess uneaten food decaying in the tank. Closely observing their feeding response ensures they are getting adequate nutrition without overfeeding.
Bioload
These fishes produce a relatively small amount of waste given their diminutive size and moderate metabolic rates. A well-established biological filtration system and regular protein skimming can easily handle their output. Routine water changes are sufficient to maintain pristine water quality and a healthy environment. Overfeeding should be carefully avoided to prevent unnecessary spikes in bioload and nutrient accumulation.
Flow
Moderate
These species thrive in moderate to strong water flow that realistically mimics the dynamic currents of their natural coral reef environment. Excellent water movement helps keep their environment properly oxygenated and carries suspended food particles past their favorite hiding spots. Furthermore, adequate flow aids in keeping the tank free of detritus accumulation, which is essential for maintaining high water quality. Powerheads should be strategically positioned to create varied and turbulent flow patterns.
Jump risk
Yes
Like many similar reef fishes, they possess a sleek, torpedo-like body shape that allows them to dart quickly when navigating the rockwork. This agility makes them exceptionally prone to jumping out of the water when startled, harassed, or simply exploring. A tightly fitting lid, glass canopy, or fine mesh screen is absolutely essential to prevent them from tragically escaping the aquarium. Open-top aquariums are highly discouraged for these species, and immense caution is required during routine maintenance.
Reproduction
Oviparous
They are well-known to be secretive cave spawners, where the male actively entices a receptive female into a secluded crevice to lay a mass of sticky eggs. After fertilization, the male vigorously guards, cleans, and aerates the egg mass until the fry hatch a few days later. Breeding in the home aquarium is certainly possible but presents a massive challenge, primarily due to the immense difficulty of providing appropriate microscopic live foods for the tiny larvae. Providing numerous complex rocky caves dramatically increases the likelihood of spawning behavior if a compatible pair is established.
Compatibility & tankmates
Highly aggressive
They are highly territorial and generally aggressive towards smaller or similarly shaped fishes, especially other benthic species. They should not be kept with peaceful, shy species as they will likely harass them relentlessly. It is best to house them with larger, robust tank mates such as moderately sized angelfishes, tangs, or larger damselfishes. Caution is advised when keeping them with small ornamental shrimp, as these invertebrates may be viewed as a natural food source.
Tank level
Bottom
They primarily inhabit the lower to middle vertical regions of the aquarium, consistently staying close to the complex rockwork. They spend a significant majority of their time cryptically darting in and out of tight caves, crevices, and rocky overhangs. While they may bravely venture out into open water columns during feeding time, they always quickly retreat to the safety of their established territory. A tank equipped with intricate and porous aquascaping provides the perfect ideal environment for their natural benthic behaviors.

Window to the official scientific data of the species

Data synced on: 06/15/2026

Scientific Parameters & Models

Trophic level
3.5 ± 0.5 se
Phylogenetic uniqueness (PD50)
0.5
Bayesian Length-Weight
a = 0.00501, b = 3.1
VulnerabilityLow vulnerability (10 / 100)

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Last updated: 06/30/2026
Tono's Dottyback (Pseudochromis tonozukai) Care Guide & Tank Setup | Atlarium