Cichlids (Cichlidae)

OB Mbuna

Pseudotropheus crabro

A form of:Bumblebee Cichlid

The OB Mbuna form (OB Mbuna) represents an example of natural polymorphism, characteristic of some species of Malawian cichlids. These fish inhabit the African Lake Nyasa and are distinguished by their peculiar coloration.

Tank
from 180 L (48 gal)
Temperature
24 – 28 °C (75 – 82 °F)
Size in aquarium
10 – 15 cm (3.9 – 5.9 in)
Acidity
pH 7.6–8.8
Natural rangeRange on the map
  • Lake Malawi area
  • Malawi
  • Mozambique
  • Tanzania

Tank conditions

Plan the tank stocking
Temperature
24 – 28 °C (75 – 82 °F)
Water pH
Slightly alkaline (7.6) – Alkaline (8.8)
Water dH
Medium hardness (10) – Very hard (25)
Water salinity
no salt (freshwater)
Size in aquarium
10 – 15 cm (3.9 – 5.9 in)
Lifespan
8 years
Temperament
Aggressive Aggressive / incompatible / unfriendly
Toward small fish
not a predator
Required aquarium volume
from 180 L (48 gal)
Lighting
moderate (regular)
Substrate
sand or gravel + stones/boulders
Water flow
weak or moderate
Swimming level
near the bottom
Feeding
Mixed diet meat + plant-based
Keeping
Harem 1 male and several females
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (harem (1 male and several females)), footprint, decor and tank mates.

Care and keeping

Description

OB Mbuna (OB Mbuna) is a natural color variation (morph) of some Mbuna cichlid species from Lake Malawi. The coloration is characterized by the presence of dark spots on the main body background, caused by an uneven distribution of melanin pigment. Almost all individuals with this type of coloration are females. The body shape is typical for representatives of the group: dense, moderately elongated, with a large mouth and well-developed fins.

Habitat

In nature, these fish inhabit the African Lake Malawi (Nyasa), predominantly in coastal areas with rocky bottoms. The typical biotope consists of rocky areas with an abundance of caves and grottoes, providing shelter. Water parameters in their natural environment are characterized by high hardness and alkaline reaction: pH 7.6–8.8, dGH 8–25, water temperature 24–28°C.

Behavior and Compatibility

These fish have a rather temperamental and quarrelsome nature. In a closed aquarium ecosystem, it is recommended to form a group of one male and several females. If the aquarium is large enough, several hundred liters, cohabitation with other Malawian cichlids is possible. Otherwise, there is a risk of conflicts between males, which can lead to the death of weaker individuals.

Care and Maintenance

Keeping these fish is similar to the conditions required for other Mbuna. For a group of 5–6 individuals, a spacious aquarium of 150 to 200 liters will be needed. The decor should include a sandy substrate, as well as rock and driftwood formations. It is important to provide a sufficient number of shelters, such as caves, where subdominant fish or females can find refuge during spawning. The hydrochemical composition of the water is of key importance for successful keeping, as it differs significantly from most freshwater biotopes. For Lake Nyasa cichlids, it is critical to maintain high pH (7.6–8.8) and dGH (8–25) values. Aquarium maintenance includes two main procedures: weekly partial water changes with fresh water and constant removal of organic residues, such as uneaten food and excrement.

Diet

In their natural habitat, these fish feed by scraping algal growths from the surface of stones and rocks. Along with algae, their diet includes small crustaceans, insects, and other invertebrates. Thus, the daily diet in the aquarium should be balanced and include both plant and protein components. For beginner aquarists, specialized Mbuna cichlid foods, available from manufacturers in various forms such as flakes, pellets, or tablets, will be an optimal choice.

Breeding and Reproduction

Reproduction occurs according to the typical scenario for Malawian cichlids, with the female incubating the eggs in her mouth. During the spawning period, the male prepares a spot on a rock or substrate. After laying and fertilizing the eggs, the female collects them into her mouth, where development lasts about 3 weeks. During this time, the female does not feed and needs peace. Fry, after emerging from the mother's mouth, are capable of self-feeding on Artemia nauplii.

Diseases

The main threat to their health is the so-called “Malawi bloat,” which often occurs when water parameters are disturbed or the diet is unbalanced. Fish are sensitive to the accumulation of nitrogenous compounds (ammonia, nitrites, nitrates). To prevent diseases, it is necessary to ensure powerful filtration, aeration, and weekly water changes, as well as to avoid overfeeding with protein-rich food.

How to choose

When purchasing, choose active fish with clean fins and no external damage or sores on their bodies. It is important to ensure that the fish exhibit typical Mbuna behavior: actively exploring the space or occupying shelters. It is recommended to avoid individuals with sunken bellies or unnaturally bloated abdomens, which may indicate digestive problems or the presence of internal parasites.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does OB Mbuna get?

An adult reaches 10–15 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does OB Mbuna need?

The recommended volume is 180 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does OB Mbuna need?

Temperature 24–28 °C, pH 7.6–8.8, hardness 10–25 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does OB Mbuna live?

Around 8 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is OB Mbuna aggressive?

Temperament: aggressive / incompatible / unfriendly. Keep this in mind when choosing tank mates.

How many OB Mbuna should be kept together?

Recommended setup: harem (1 male and several females). Ignoring this is a common cause of stress and disease.

What does OB Mbuna eat?

Diet type: mixed diet (meat + plant-based). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of OB Mbuna?

The scientific name of the species is Pseudotropheus crabro, family Cichlids (Cichlidae). It also appears in the literature as: Melanochromis crabro.

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Other scientific names and conservation status

Other scientific names
Melanochromis crabro
Pseudotropheus crabro
formerly Maylandia crabro
Categories
Cichlids