Yellow Tail Acei (Pseudotropheus sp. acei): Care, Types, Reproduction, and Feeding

The vast and biodiverso Lake Malawi, one of the African Great Lakes, is a treasure for aquarists worldwide. It hosts an incredible variety of cichlids, fish known for their vibrant colors, complex behaviors, and fascinating reproductive strategies. Among the multitude of species inhabiting its rocky and sandy waters, one stands out for its unique combination of beauty, relatively peaceful behavior, and a surprising tendency to swim in schools: the Yellow Tail Acei (Pseudotropheus sp. acei).

The Yellow Tail Acei belongs to the Mbuna group of cichlids from Lake Malawi. The term “Mbuna” means “rock-hitter” in the local Tonga language, aptly describing the behavior of most of these fish, which inhabit the rocky areas of the lake, scraping algae (known as “aufwuchs”) from rock surfaces. The species Pseudotropheus acei has different geographical variants such as Pseudotropheus acei Luwala, Pseudotropheus acei Itungi, Pseudotropheus acei Tanzania, and Pseudotropheus acei Msuli.

In this article, we will analyze in detail the aquarium care for the Yellow Tail Acei Pseudotropheus sp. acei, including ideal tank setup, diet, and the crucial selection of breeders. We will unravel the secrets of its reproduction, learn how to differentiate males and females, and follow its development from juvenile to adult.

Characteristics of the Yellow Tail Acei (Pseudotropheus sp. acei)

Taxonomy and Classification

To fully understand the Pseudotropheus acei cichlid, let’s look at its place in the tree of life:

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Cichliformes

Family: Cichlidae

Subfamily: Pseudocrenilabrinae

Tribe: Haplochromini

Genus: Pseudotropheus

Species: Pseudotropheus acei (although often referred to as Pseudotropheus sp. “acei,” indicating its exact taxonomic status may be subject to revision or that multiple distinct populations exist).

Common name in Spanish: Acei, cíclido púrpura, cíclido morado, cíclido de cola amarilla

Common name in English: Yellow tail acei.

Physical Description

The Yellow Tail Acei is a fish of undeniable beauty. Its most striking feature is the sharp contrast between its body and fins.

• Body Coloration: The body is a steel blue to iridescent purple color, which can vary in intensity depending on the fish’s mood, health, dominance, and geographic origin.

• Fin Coloration: All its fins (dorsal, caudal, anal, pelvic, and pectoral) are a vibrant yellow to orange-yellow color. This is the feature that gives it its common name “Yellow Tail.” The intensity of the yellow can also vary.

• Body Shape: It has the elongated and robust body typical of many Mbunas, adapted for swimming among rocks but also capable of moving agilely in open waters.

• Scales: Like the vast majority of bony fish, Pseudotropheus acei is covered in cycloid scales, which provide protection. Confusion often arises because “Yellowtail” is also the common name of a popular marine fish (Seriola lalandi), which is completely unrelated to our African cichlid.

• Size: Under proper aquarium conditions, the Yellow Tail Acei typically reaches an adult size of between 12 to 15 centimeters (approximately 5-6 inches) in total length. Males can become slightly larger than females.

Origin and Natural Habitat

The Yellow Tail Acei is endemic to Lake Malawi, specifically found in various locations along its coasts. It prefers habitats that combine rocky areas with sandy zones and, distinctively, is strongly associated with submerged logs and wood, where they graze on algae and find shelter. This association with wood is unusual for Mbunas, which are typically strictly linked to rocks.

Pseudotropheus acei somewhat breaks the typical Mbuna mold. While many Mbunas are extremely territorial and solitary outside the breeding season, the Acei is notably more sociable and is often observed swimming in large schools in open water, especially over sandy areas with submerged logs. This characteristic makes it a more manageable and visually dynamic option for African cichlid community aquariums, provided its needs are met.

On the other hand, Msukwa et al. (2021) classified Pseudotropheus sp ‘acei’ in the medium vulnerability category based on the PSA (Productivity Sustainability Analysis), meaning there is a moderate risk of overexploitation in its natural habitat due to the ornamental fish export trade.

Geographical Variants: A Spectrum of Color and Origin

Lake Malawi is a crucible of speciation, and Pseudotropheus acei is no exception. Several geographically isolated populations exist that have developed subtle differences, primarily in body hue and fin color intensity. These variants are highly prized by hobbyists:

• Pseudotropheus acei Msuli (“Classic” Yellow Tail Acei): Often considered the “standard” variant or the one most commonly found in the trade. It comes from the Msuli Point area. It features the characteristic blue/purple body and vibrant yellow fins. This is the image most people have in mind when thinking of the Yellow Tail Acei.
• Pseudotropheus acei Luwala: Originating from Luwala Reef. This variant tends to have a more bluish body color and very intense yellow fins. Some specimens may show a smoother color transition between the body and the caudal fin.
• Pseudotropheus acei Itungi: Hailing from the Itungi region in Tanzania. It is often characterized by a darker body, almost bluish-black in some dominant males, which contrasts spectacularly with the bright yellow fins.
• Pseudotropheus acei Tanzania: This term can be somewhat generic, as several locations are in Tanzania (like Itungi). Generally, it refers to populations from the Tanzanian coast that may show variations in the depth of the body’s blue and the brightness of the yellow in the fins. It is important to know the specific locality if seeking a particular variant.
• Pseudotropheus acei Ngara White Tail: This is a distinct and highly sought-after variant. As its name suggests, instead of yellow fins, the Pseudotropheus acei Ngara White Tail has fins, especially the caudal fin, that are bright white or pale bluish-white. The body is usually a lighter blue or even grayish compared to the yellow-tailed variants. It is an equally attractive fish but with a different color palette.

It is important to note that the differences between some yellow-tailed variants (Msuli, Luwala, Itungi) can be subtle and often depend on the quality of the specimens, their mood, and the aquarium conditions. The White Tail variant (Ngara) is the most clearly distinct.

The Ideal Aquarium for the Yellow Tail Acei

Recreating a suitable environment is fundamental for the health and well-being of the Yellow Tail Acei. Given their schooling behavior and adult size, they require a spacious and well-configured aquarium.

Tank Size

Due to their gregarious nature and need for swimming space, a minimum tank size of 200-250 liters (approximately 55-75 gallons) is recommended for a small group (5-6 individuals) of Yellow Tail Acei. However, a larger tank, 300 liters (75 gallons) or more, is preferable, especially if planning to keep them with other cichlids. Longer tanks are better than tall tanks to provide more horizontal swimming space.

Substrate

A fine sand substrate is ideal. Malawi cichlids enjoy digging and sifting through the sand looking for food. Sand also helps buffer the pH and hardness, keeping them in the alkaline ranges these fish need. Aragonite sand or crushed coral can be used (or mixed in) to help maintain high pH and kH levels.

Decoration and Structure

Although they swim in open water more than other Mbunas, they still appreciate structure and refuges.

• Rocks: Build stable rock formations that offer caves, crevices, and hiding places. This is crucial for reducing aggression and allowing fish to establish territories or retreat if harassed. Ensure the rocks are well-seated on the bottom of the tank (or on a polystyrene/styrofoam panel) before adding the sand to prevent fish from undermining them and causing collapses.
• Open Space: Leave significant areas of open space for swimming, as Acei enjoy patrolling in groups.
• Wood (Optional but Natural): Adding one or two large, smooth logs (mopani, aquarium-safe driftwood) can mimic their natural habitat and provide additional surfaces for algae grazing. However, be cautious, as wood tends to lower pH, which is contrary to the needs of Malawi cichlids. If using wood, monitor the pH closely and use buffers or calcareous substrates if necessary to keep it high.

Water Parameters

The Yellow Tail Acei, like other Lake Malawi cichlids, requires hard, alkaline water. Stability is key. In Table 1, we present the main water quality parameters for the care of Yellow Tail Acei.

Table 1. Water quality parameters for keeping Yellow Tail Acei Pseudotropheus sp. acei in aquariums.

Filtration

African cichlids, like the Yellow Tail Acei, are robust fish that produce a considerable amount of waste. Powerful and efficient filtration is required. An external canister filter or two large hang-on-back (HOB) filters, with a total flow rate of at least 4-6 times the aquarium volume per hour, is a good rule of thumb. Good water circulation also helps oxygenate the tank.

Lighting

Moderate lighting is sufficient. Lights that are too bright can cause the fish to become shy or lose color. Lighting that promotes healthy algae growth on rocks is beneficial, as it provides a natural food source.

Tank Maintenance

Regular water changes are crucial for keeping nitrates low and replenishing trace minerals. Changing 30% to 50% of the water weekly is recommended, depending on the tank’s bioload. Ensure the new water has parameters (temperature, pH, hardness) similar to the aquarium’s to avoid shock.

Diet and Nutrition of the Yellow Tail Acei

In the wild, Pseudotropheus acei feeds primarily on “aufwuchs,” the complex matrix of filamentous algae, diatoms, small crustaceans, and invertebrates that grow on rocks and submerged wood. Therefore, in the aquarium, their diet should be predominantly herbivorous.

Staple Food

A high-quality commercial food in pellet or flake form, specifically formulated for herbivorous African cichlids, should form the base of their diet. Look for foods with ingredients like Spirulina, Chlorella, and other algae or vegetables.

In this regard, Yiğit et al. (2019) reported that the tails of fish fed a diet containing red pepper (Capsicum annuum) showed a significant increase in pigmentation; while Zhang et al. (2020) highlight that spirulina can improve the reproductive performance of the yellow tail cichlid (Pseudotropheus acei).

Supplementary Foods

• Vegetable Supplements: Supplement their diet several times a week with fresh vegetables like spinach, romaine lettuce (without the core stem), peas (skinned), zucchini, or cucumber. Be sure to remove any uneaten leftovers after a few hours to avoid polluting the water.
• Foods to Avoid or Limit: Avoid foods high in animal protein, especially those derived from mammals (like beef heart), as they can cause serious digestive problems such as “Malawi Bloat.” Protein-rich foods like brine shrimp or mysis shrimp can be offered occasionally as a treat (once a week or less), but should not be the staple of the diet.
• Feeding Frequency: Feed adults once or twice a day with small amounts they can consume in about 30-60 seconds. Juveniles may require more frequent feedings (2-3 times a day). It is better to slightly underfeed than overfeed.

Social Behavior and Temperament

The Yellow Tail Acei is one of the most peaceful Mbunas, but “peaceful” is a relative term in the world of Malawi cichlids.

• Gregarious Behavior: Its most distinctive trait is its tendency to form schools. Yellow Tail Acei feel safer and exhibit more natural behavior when kept in groups of at least 5-6 individuals. A larger group (8+) in a suitable tank can be even better, helping to distribute aggression.
• Intraspecific Aggression: Although they swim together, a social hierarchy still exists. There may be some aggression among male Yellow Tail Acei, especially if space or the number of females is limited. Maintaining a ratio of at least 1 male for every 3-4 females can help mitigate this.
• Interspecific Aggression: They are generally less aggressive towards other Mbuna species compared to fish like Metriaclima estherae (Red Zebra) or Melanochromis auratus. However, they will defend their small territory, especially during breeding. Their relative peacefulness makes them a good option for carefully planned Mbuna community tanks.

Compatibility: Ideal Tank Mates

Choosing the right tank mates is crucial for the success of an African cichlid aquarium. For the Yellow Tail Acei, consider the following:

• Similar Requirements: Tank mates must thrive in the same hard, alkaline water conditions and have similar dietary requirements (primarily herbivores or omnivores with a herbivorous tendency).
• Compatible Temperament: Look for other Mbunas considered “relatively peaceful” or moderately aggressive. Avoid extremely aggressive or territorial species that could intimidate or harm the Acei.
• Similar Size: Companions should have a comparable adult size to prevent predation or excessive harassment.
• Avoid Hybridization: Do not keep different geographical variants of Pseudotropheus acei together (e.g., Yellow Tail with White Tail) if you wish to maintain pure lines, as they can hybridize. Also, avoid keeping them with other Pseudotropheus species that are very similar in shape and color with which they could crossbreed.

Good Tank Mate Options

• Labidochromis caeruleus (Yellow Lab): A classic companion. They are peaceful, have a similar diet, and their bright yellow color contrasts wonderfully with the Acei’s blue.
• Iodotropheus sprengerae (Rusty Cichlid): Another relatively peaceful, moderately sized Mbuna with interesting purple/rusty coloration.
• Cynotilapia sp. (e.g., C. afra): Many Cynotilapia species are compatible in size and temperament, although some can be a bit more territorial. Research the specific species.
• Other “Peaceful” Pseudotropheus: Species like Pseudotropheus saulosi (where males and females have different colors) can work, but require a large tank and careful aggression management.
• Synodontis Catfish from Lake Tanganyika: Species like Synodontis multipunctatus (Cuckoo Catfish) or S. petricola (Dwarf Synodontis) are excellent bottom dwellers that tolerate the same water conditions and help clean up leftover food.

Poor Tank Mate Options

• Very Aggressive Mbunas: Avoid species like Melanochromis auratus, Metriaclima lombardoi, Labeotropheus trewavasae, or Pseudotropheus crabro.
• Haps and Peacocks (Aulonocara): Although sometimes mixed in very large tanks, their diets (more carnivorous) and temperaments (generally less aggressive, but males can be territorial) can conflict. Peacocks, in particular, can be easily stressed by the constant activity of Mbunas. If attempted, it requires a very large tank (6 feet or longer) and careful species selection.
• Non-Cichlid Fish: Most tropical community fish (tetras, barbs, guppies, etc.) are incompatible due to different water needs (they prefer soft, acidic water) and because they would quickly be harassed or eaten.
• Cichlids from Other Continents: Avoid mixing African cichlids from Malawi with South or Central American cichlids due to drastic differences in water requirements and temperament.

The key to a successful community tank with Acei is a large tank, plenty of rockwork to create visual barriers and hiding places, and controlled slight overstocking (to distribute aggression) combined with excellent filtration and frequent water changes.

Reproduction of Pseudotropheus sp. acei

Sexual Differentiation between Males and Females

Distinguishing between male and female Yellow Tail Acei can be challenging, especially in young individuals. They do not exhibit marked sexual dimorphism like some other cichlid species. However, there are some subtle clues, especially in mature adults:

• Size: Adult males are usually slightly larger and more robust than females of the same age.
• Color Intensity: Dominant male Yellow Tail Acei may display more intense blue/purple colors and brighter yellow fins, especially during courtship or territorial disputes. However, this is not an absolute rule, as healthy females can also be very colorful, and subordinate males may appear duller.
• Fin Shape: Sometimes, adult male Yellow Tail Acei may have slightly more pointed dorsal and anal fins at their posterior ends compared to females, which tend to have rounder fins.
• Egg Spots: These are the yellow/orange spots on the anal fin. Traditionally, it was thought that only males had them or that they had more and larger ones. However, in P. acei, both males and females can have egg spots, although males tend to have more and/or larger, brighter ones. It is not a 100% reliable indicator on its own.
• Venting (Sexing by Genital Vents): This is the most reliable method for sexing adults, but it requires removing the fish from the water and examining its ventral openings (located just in front of the anal fin). There are two openings: the anus (closer to the head) and the urogenital opening (closer to the anal fin). In males, both openings are similar in size and round (o o). In females, the urogenital opening is noticeably larger, often slit-shaped or like a wide U, to allow eggs to pass (O o). This requires practice and good eyesight.

The most practical way to ensure a mix of sexes for breeding is to buy a group of 6-8 juveniles and let them grow together. As they mature, subtle differences and breeding behaviors will reveal the sexes.

Reproductive Process of the Yellow Tail Cichlid

The Yellow Tail Acei is relatively easy to breed in the aquarium if the right conditions are provided. They are maternal mouthbrooders, meaning the female carries the fertilized eggs in her mouth until they hatch and the fry are able to swim freely.

Preparation and Triggers

• Water Conditions: Maintain impeccable water quality with stable parameters within the ideal range.
• Nutritious Diet: A varied, vegetable-rich diet ensures the fish are in good breeding condition.
• Healthy Group: You need at least one mature, healthy male and female. A larger group with multiple females per male is ideal.
• Triggers: Often, a slightly larger water change or a slight increase in temperature (within the safe range) can simulate seasonal changes and stimulate spawning.

The Spawning Process

• Courtship: The male will intensify his colors and begin courting a receptive female. He may clean an area of the substrate or a flat rock, vibrating and displaying his flanks and fins to attract her.
• “T” Position Spawning: The female Yellow Tail Acei will lay a few eggs on the prepared site. Then, the male will position himself in front of her, displaying his anal fin with the egg spots. The female, attempting to pick up these “egg spots,” will stimulate the male to release sperm, thus fertilizing the eggs she either already has in her mouth or picks up immediately after fertilization.
• Egg Collection: The female will quickly collect the fertilized eggs in her mouth. This process is repeated until all eggs have been laid and fertilized (usually between 20 and 60, depending on the size and age of the female).

Mouthbrooding

• Incubation: Once spawning is complete, the female Yellow Tail Acei will retreat to a quiet place in the aquarium, often near the rocks or in a cave. She will stop eating and hold the eggs in her buccal pouch (gular pouch), which will appear noticeably swollen. She will gently “chew” or tumble the eggs inside her mouth to keep them clean and oxygenated.

Care of the Holding Female

• Stress: It is crucial not to stress the female during this period. Avoid drastic changes in the aquarium or chasing her. Other fish may harass her; if this is severe, you might consider moving her to a separate breeding/hospital tank with water from the main tank. However, moving her can also cause stress and lead her to spit out or swallow the eggs. It is often best to leave her in the main tank if she has sufficient hiding places.
• Duration: Incubation lasts approximately 21 to 28 days, depending on the water temperature.

Release of Fry

• Release: The female Yellow Tail Acei will release the fry when she feels they are large enough and the environment is safe. The fry will already be fully formed and capable of swimming and feeding themselves. In a community aquarium, most fry will be quickly preyed upon by other fish, including their own parents.

Raising and Caring for the Fry

If you wish to raise a significant number of fry, you have two main options:

• “Stripping” (Manual Extraction): Around day 18-20 of incubation, you can carefully catch the female and gently persuade her to release the fry into a separate rearing tank. This requires some skill and can stress the female, but ensures the survival of most fry.
• Moving the Female: Move the female to a rearing tank a few days before the expected release date. Once she releases the fry, you can return her to the main tank to recover and feed.

The rearing tank should have water from the main tank, a gentle sponge filter (to avoid sucking up the fry), and some small hiding places. Feed the newborns fine powder food, very finely crushed flakes, or newly hatched baby brine shrimp 3-4 times a day. Perform small, frequent water changes in the rearing tank to maintain water quality. As they grow, you can gradually transition to larger foods.

Health and Common Diseases

Yellow Tail Acei are hardy fish when kept in proper conditions. However, like all African cichlids, they are susceptible to certain ailments, often related to stress, poor water quality, or an improper diet.

Ich (White Spot Disease)

Ich is caused by the parasite Ichthyophthirius multifiliis. It manifests as small white spots on the body and fins. Treatment usually involves raising the temperature (if safe for all inhabitants) and/or using specific medications.

Malawi Bloat

A serious and often fatal condition primarily affecting herbivorous Mbunas, like the Yellow Tail Acei. It is believed to be related to an incorrect diet (too much animal protein), stress, or internal intestinal parasites. Symptoms include abdominal swelling, loss of appetite, white stringy feces, and difficulty breathing. Prevention (proper diet, good water quality, low stress) is key. Treatment is difficult and often requires medications like Metronidazole.

Bacterial/Fungal Infections

These can occur secondary to injuries or stress. They manifest as frayed fins, cottony patches, ulcers, etc. Treatment depends on the specific cause and may require antibiotics or antifungals.

Prevention

The best strategy is prevention:

• Maintain excellent water quality with regular changes.
• Provide an appropriate and varied, primarily herbivorous diet.
• Avoid overcrowding and provide sufficient hiding places to reduce stress.
• Quarantine new fish for 4-6 weeks before introducing them to the main tank.
• Observe your fish daily for any early signs of disease.

Conclusion

The Yellow Tail Acei (Pseudotropheus acei) is undoubtedly one of the most attractive and rewarding Mbuna cichlids to keep in an aquarium. Its stunning blue/purple coloration contrasted with bright yellow fins, manageable size, and unique social behavior distinguish it from many of its more aggressive relatives from Lake Malawi.

From the classic Pseudotropheus acei Msuli to regional variants like Luwala, Itungi, Tanzania, or the distinctive Ngara White Tail, there is an Acei form to captivate almost any hobbyist. Understanding their specific needs – a spacious tank, hard and alkaline water, a herbivorous diet, and the company of their own species and compatible tank mates – is essential for their well-being.

The relative ease with which they reproduce via mouthbrooding adds another layer of fascination, allowing aquarists to observe one of nature’s most interesting reproductive behaviors and raise their own fry. Knowing how to differentiate between males and females can be challenging, but it is part of the learning and observation that make fishkeeping such an absorbing hobby.

In summary, the Yellow Tail Acei (Pseudotropheus acei) is not just a beautiful fish; it is a window into the incredible diversity and evolution of Lake Malawi. With proper care, this African cichlid can be a vibrant and dynamic centerpiece in any well-planned African cichlid aquarium for many years.

References

Msukwa, A. V., Cowx, I. G., & Harvey, J. P. (2021). Vulnerability assessment of Lake Malawi’s ornamental fish resources to export ornamental trade. Fisheries Research, 238, 105869. https://doi.org/10.1016/j.fishres.2020.105869

Yiğit, N. Ö., Koca, S. B., Özmen, Ö., Didinen, B. İ., & Metin, S. (2019). The effects of dietary administration with high level red pepper (Capsicum annuum) on growth performance, coloration, histology and protection against Aeromonas sobria in Yellow Tail Cichlid, Pseudotropheus acei. Acta Aquatica Turcica, 15(3), 340-346.

Zhang, F., Man, Y. B., Mo, W. Y., & Wong, M. H. (2020). Application of Spirulina in aquaculture: A review on wastewater treatment and fish growth. Reviews in Aquaculture, 12(2), 582-599. https://doi.org/10.1111/raq.12341

Milthon Lujan

Editor at the digital magazine AquaHoy. He holds a degree in Aquaculture Biology from the National University of Santa (UNS) and a Master’s degree in Science and Innovation Management from the Polytechnic University of Valencia, with postgraduate diplomas in Business Innovation and Innovation Management. He possesses extensive experience in the aquaculture and fisheries sector, having led the Fisheries Innovation Unit of the National Program for Innovation in Fisheries and Aquaculture (PNIPA). He has served as a senior consultant in technology watch, an innovation project formulator and advisor, and a lecturer at UNS. He is a member of the Peruvian College of Biologists and was recognized by the World Aquaculture Society (WAS) in 2016 for his contribution to aquaculture.