Mchenga thinos

Mchenga thinos

Mchenga thinos was first described by Stauffer, LoVullo & McKaye in 1993. As far as we know, there is no generally recognized common name for Mchenga thinos. In the aquarium hobby, the scientific name is often used, or a derivative thereof.

This fascinating fish belongs to the family Cichlidae, better known as the cichlids. Cichlids are a very diverse group of fish found worldwide, but the Mchenga thinos is specifically a representative of the subfamily Pseudocrenilabrinae, found mainly in Africa.

The name of the genus, Mchenga, is derived from Chichewa, the indigenous language of Malawi. The word “mchenga” means “sand” and refers to the sand castles or “bowers” that males of this genus build as part of their breeding behavior. The genus name was established by Stauffer and Konings in 2006. The species name, thinos, comes from Greek and means “sand mound,” which is also a reference to the sand structures the males create for reproduction.

Historically, this species was also known by another scientific name. The only valid synonym for Mchenga thinos is Copadichromis thinos (Stauffer, LoVullo & McKaye, 1993). This was the original combination when the species was first described, before it was later placed in the genus Mchenga.

Description

Mchenga thinos have a typical cichlid body shape, which is generally streamlined and somewhat laterally flattened, making them agile in the water. In terms of size, these fish reach about an average total length of 9 centimeters. However, the dominant males can grow slightly larger, up to 10 centimeters. In the aquarium where we sometimes feed them too much and too vigorously, they sometimes get a little bigger up to about 14 centimeters.

The color and patterns of the Mchenga thinos depend on gender and age. Adult males are particularly striking with their metallic blue coloration. They often have a distinct white stripe on their dorsal fin and distinctive egg spots on their anal fin. These egg spots are small, round spots that resemble fish eggs and play an important role in reproduction. Females and juvenile fish, on the other hand, are predominantly silver in color. Females may also have yellow spots on their anal fin, although these are less prominent than the egg spots in males.

Differences between Males and Females (Sexual Dimorphism)

The differences between males and females, also known as sexual dimorphism, are evident in the Mchenga thinos.

Physical differences: As mentioned earlier, males are generally larger than females. The most striking difference, however, is in the coloration. Males show off their metallic blue hue, the white stripe on the dorsal fin and the distinctive egg spots on the anal fin. Females and juveniles retain a more subdued silvery appearance, with females sometimes showing yellow spots on the anal fin.

Differences in behavior: There are also distinct differences in behavior. Dominant males are polygamous, meaning they reproduce with several females each season. An important part of their reproductive behavior is building sandcastles or craters on the bottom. These structures serve as breeding grounds and are intended to attract females. After spawning, the females take charge of the young. They swim in larger groups and eventually release their young into shallow water, where they are safer. Young fish resemble the females in color and are silver in color.

Behavior and Temperament

Mchenga thinos is generally a peace-loving fish species that thrives in a community aquarium. They are known for not caring much about other fish that cross their path. This makes them a suitable choice for multi-species aquariums, as long as the co-inhabitants are not too aggressive.

These fish naturally live in schools or larger groups. Therefore, it is essential to keep them in a group of at least five individuals to ensure their well-being. Solitary fish become stressed quickly, making them more susceptible to disease. Although they live in groups, they can also function well in pairs or in a group with several females per male, which is advisable given their polygamous nature. A ratio of three females to one male is often considered a good compromise for group composition.

As for their habitat, Mchenga thinos are fish that inhabit both mid-depth and near the bottom. They are mainly found in open water above sandy bottoms or in the transition zones between sandy and rocky bottoms, at depths ranging from 5 to 25 meters. A notable behavioral characteristic is their tendency to dig in the sand to alter their environment, especially the males who build sand craters for reproduction.

Life expectancy

In a properly maintained aquarium, Mchenga thinos fish can reach a respectable age. The average life expectancy for this species in captivity is about 7 years. No information is available about their life expectancy in the wild.

Biotope

Mchenga thinos is an endemic species, meaning that it occurs naturally only in one specific geographic region. These fish are widely found in Lake Malawi. Lake Malawi is one of the largest lakes in Africa and borders the countries of Malawi, Mozambique and Tanzania. The species can be found throughout the lake, often in large groups. One specific location listed as a “type locality” (the place where the species was first discovered and described) is Queens Reef in Mazinzi Bay.

Natural Habitat

The natural habitat of the Mchenga thinos is characterized by open water over sandy bottoms or in the so-called “transition zones. These transition zones are areas where sandy bottoms gradually turn into rocky structures. The fish are usually found at depths ranging from 5 to 25 meters.

As for underwater vegetation, these fish live primarily in open water over sandy areas. This implies that there is generally little to no dense underwater vegetation present in their immediate habitat. The focus is more on the sandy flats and the alternation with rock formations.

The soil or substrate in their natural habitat consists mainly of sand. In the transition zones, the soil consists of a mixture of sand and stones. This sandy substrate is of great importance to the Mchenga thinos, as the males build sandcastles or craters as part of their reproductive behavior.

Natural Enemies and Hunting Behavior

Mchenga thinos feed mainly on plankton in Lake Malawi. Plankton consists of small organisms floating in the water. Because of this diet, the Mchenga thinos is classified as a carnivorous (carnivorous) cichlid. Although they hunt plankton themselves, there is no specific mention of their natural enemies in Lake Malawi in the available information. As with many smaller cichlids in large lakes, they are likely to prey on larger predatory fish and birds.

Diet

What does this fish species eat in the wild?

In their natural habitat, Mchenga thinos are specialized eaters. This species of fish is planktivorous, meaning they feed primarily on plankton. More specifically, they hunt zooplankton. Zooplankton are small animal organisms that float freely in the water. They forage (search for food) in the water column, meaning they swim through the open water to catch their food. Because of this diet of small animal organisms, the Mchenga thinos is classified as a carnivorous (carnivorous) cichlid.

What do you feed this fish species in the aquarium?

In the aquarium, the Mchenga thinos is fortunately not picky and accepts a wide range of food types. However, it is important to offer a varied diet to avoid deficiencies and ensure the health of the fish.

Suitable food options for Mchenga thinos in the aquarium include:

• Dry food: This includes flakes and pellets. There are several commercial dry foods available that are suitable for cichlids.
• Fresh and frozen food: This is an excellent addition to the diet. Consider frozen foods such as white or black mosquito larvae, and fresh shrimp.
• Protein-rich foods: Given their natural carnivorous diet, it is advisable to emphasize protein-rich foods.

It is important not to overfeed the fish to avoid water pollution. It is better to give several small portions per day than one large meal. With wild specimens, it may sometimes be necessary to gradually accustom them to aquarium food, although most specimens available through the trade are already accustomed to commercial food.

The Aquarium

For a small group of Mchenga thinos of at least five individuals, an aquarium of at least 500 liters is recommended, with a front length of at least 150 centimeters. However, if you want to keep a larger group, for example with several males and females (a harem of 3-4 males and 5-6 females), or if you want to combine them with other fish species, an aquarium of 1,000 liters or more, with a minimum front length of 250 centimeters, is necessary.

The decoration of the aquarium should mimic the natural sandy or transitional zone of Lake Malawi. This means that the emphasis should be on sand as a substrate. Ideally, at least 80% of the bottom should consist of sand, especially if you want to mimic the sand zone. This is important because Mchenga thinos males build sandcastles or craters as part of their reproductive behavior. They are known to dig their territory in the sand, which means they can uproot plants and change the layout. Therefore, using many plants is not ideal, or you should choose very robust plants that can be well anchored.

In addition to sand, you can add some large rocks to create hiding places and visual barriers, just like in transitional zones in the wild. These rocks can also help keep the water alkaline. Adding calcareous rocks, such as millstone or travertine, can improve the environment and stabilize water values.

Also make sure that rocks are firmly fixed so that they cannot tip over while digging. For example, place the rocks on a plastic mat directly on the glass and only then add sand.

Water parameters

Mchenga thinos thrive best in water that mimics the conditions of Lake Malawi. This means:

• Temperature: The ideal water temperature is between 22°C and 26°C.
• pH value: These fish naturally live in alkaline water, so a pH between 7.5 and 8.5 is optimal.

To maintain water quality, it is recommended to change 20% to 30% of the water monthly. The use of specific salts can help stabilize the pH, depending on the hardness of the tap water used.

Suitable Tank Mates

Mchenga thinos is een relatief vredelievende vissoort die over het algemeen geen gedragsproblemen vertoont in een gemeenschapsaquarium. Ze zijn echter niet erg assertief en moeten daarom alleen worden samengehouden met andere vissoorten die een rustiger karakter hebben .

Suitable tank mates include:

• Aulonocara-species
• Certain Lethrinops-species
• Some Copadichromis-species (but not all species in this genus)

It is strongly advised against keeping Mchenga thinos together with Mbuna cichlids. Mbunas tend to be much more aggressive and dominant, which would lead to stress and eventually disease in the less assertive Mchenga thinos. It is also wise not to mix multiple species of the same genus or different varieties of the same species to avoid the risk of hybridization (crossbreeding).

Breeding aquarium and conditioning

Breeding Mchenga thinos in an aquarium is a rewarding experience, and although considered moderately difficult, it is certainly achievable with proper preparation and conditions.

Breeding Tank

Mchenga thinos is a mouthbreeder, meaning that the female carries the fertilized eggs and later the young fish in her mouth for protection. Reproduction of this species usually takes place in the regular aquarium, provided the conditions are optimal and the aquarium is large enough.

Aquarium decoration plays an important role. Because males build sand castles or craters as part of their courtship behavior and reproduction, a bottom of fine sand is essential. Make sure there is enough room to build a sandcastle. In the aquarium, the sand castle is often a bit smaller than in the wild due to the limited space in the aquarium.

Conditioning and Group Composition

To bring the fish into breeding condition, a varied and protein-rich diet is very important. In the wild, Mchenga thinos feed mainly on zooplankton. For conditioning, you can feed them with high-quality dry foods (flakes and pellets), supplemented with fresh and frozen foods such as white or black mosquito larvae and fresh shrimp. It is recommended to emphasize protein-rich foods to optimally prepare the fish for breeding. Feed several small portions per day instead of one large meal to avoid water pollution.

Mchenga thinos is a polygamous fish species, meaning that one male mates with several females. For a breeding group, a harem arrangement is very suitable. A ratio of one male to three females is a good option. For larger aquariums and larger groups, a ratio of, say, 3-4 males and 5-6 females is possible, provided the aquarium is at least 1000 liters with a front length of 250 centimeters.

The Spawn

During the spawning period, the colors of the fish, especially those of the male, become more intense and vibrant. The dominant male, already normally metallic blue in color, will display this hue even deeper and shinier to attract females. The distinctive egg spots on his anal fin play an important role in the spawning ritual. The absence of black markings in the tail fin of the breeding male, unlike other Mchenga species, is also a diagnostic feature during this period.

Courting begins with the male creating a suitable nesting site. He does this by building a sand castle or crater on the sandy bottom of the aquarium. This sand structure serves as his territory and the place where mating will take place. The male will then lure the female to his bower with his impressive colors and behavior.

The Spawn

When a female is interested, she will follow the male to his sand crater. Mating takes place in this specially prepared sand structure. The couple orbits each other just above the sand. The female deposits her eggs at the bottom of the crater.

Immediately after the female deposits the eggs, the male will fertilize them. Then the female quickly takes the fertilized eggs into her mouth. The egg spots on the male’s anal fin play a clever role in this process: the female tries to take these spots, which resemble eggs, into her mouth as well. When she does this, she opens her mouth and the male can release his sperm, thus fertilizing the eggs in her mouth after all.

Mchenga thinos is a polygamous species, meaning that one male can reproduce with multiple females during the season. This explains why a harem arrangement (one male with multiple females) is recommended in the aquarium.

Raising the Young Fish

Raising young Mchenga thinos is a careful process, heavily influenced by their unique mouthbrooding behavior. As an experienced aquarist, I can give you detailed information.

Parental Care and Development of the Fry

Mchenga thinos is a mouthbrooder, meaning the female assumes full parental care by carrying the fertilized eggs and later the young fish in her mouth for protection. This is a very effective strategy to protect the fragile eggs and larvae from predators.

After the eggs are deposited and fertilized, the female takes them directly into her mouth. The eggs hatch after a few days, but the young fish continue to grow in the female’s mouth. During this period, they feed on their egg yolk sac, which provides them with the necessary nutrients. After about three weeks after egg deposition, the female releases the young fish for the first time.

In the wild, females release their young in shallow water, where they are safer from larger predatory fish. In a community aquarium with adult fish, however, the survival rate of the young fish is often low, as they are easily eaten by other inhabitants, including the adult Mchenga thinos themselves.

The Breeding Aquarium for Juvenile Fish

If you want to raise an entire nest of young Mchenga thinos, a special breeding aquarium is needed. This offers the young fish the best chance for survival and growth.

Setting up the breeding aquarium:

• Size: An aquarium of about 40 centimeters is sufficient for rearing a nest of young Mchenga thinos.
• Filter: Furnish it with a sponge filter. This type of filter is soft and prevents the young fish from being sucked in, while still providing adequate filtration and water movement.
• Substrate: A layer of sand on the bottom is ideal. This mimics their natural environment and is easy to keep clean.
• Decoration: Place a few rocks in the aquarium. These provide hiding places for the female and later for the young fish.

Transfer the female:
To secure the young fish, catch the female with the eggs or larvae in her mouth from the main aquarium around day 17 after deposition and place her in the prepared breeding aquarium. Around day 21, she will release the young fish. A great advantage is that the female does not eat the young fish immediately after release. This gives you plenty of time to place her calmly back in the main aquarium once the young are swimming independently.

First Feed and Water Quality for Juvenile Fish

Once the young Mchenga thinos swim freely, they require very small, protein-rich food. Considering the planktivorous diet of the adult fish, the following foods are suitable as initial food:

• Fine ground flake food: Make sure the food is ground to a very fine powder so that the small mouths of the young fish can absorb it.
• Artemia nauplii: These are newly hatched brine shrimp and are an excellent source of live, protein-rich food that stimulates growth.
• Other small live or frozen foods: Consider micro-worms or cyclops.

Feed the young fish several times a day (for example, 3-5 times) in small portions. This ensures a constant supply of nutrients while preventing overfeeding and water pollution.

Maintaining clean and stable water values is important for the health and growth of young fish. For young fish, which are more sensitive to poor water quality, more frequent (e.g., weekly) and/or smaller water changes may be necessary to maintain optimal water values. Good water quality contributes significantly to the survival and healthy development of young Mchenga thinos.

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Gerard Semence – Revedimages-gerard.com
Mark Thomas – Marks Fiskenarie
Carsten Gissel