The Poll’s Tropheus is the only Tropheus cichlid to have a ‘lyre’ type tail fin!
The Poll’s Tropheus Tropheus polli is unique among the Tropheus cichlids. It can can be distinguished from the other species in the genus by a forked caudal fin rather than the fan shaped fin found on the others. The caudal fin becomes even more deeply forked as the fish ages. However its eyes resemble those of the Blue-Eyed Tropheus Tropheus brichardi, and are a bright turquoise when kept in a well-maintained aquarium.
The Tropheus became a big hit when first introduced in Germany in the mid 1970’s and then into the United States, and are still very popular today. Originally many of the imports were identified as Blunthead Cichlid Tropheus Moorii varieties, but now it is recognized that these fish represent a number of different species. There are many color morphs of the different Tropheus species, with 50 or so varieties of T. Moorii alone.
This species was described it in 1977 by G. S. Axelrod. He placed it in a category of its own due to it being the only one with the ‘lyre’ type tail fin. The tail fin was one of its differences however, it also has only 4 rays on the anal fin. The Poll’s Tropheus also has an individual place of origin and there are at least three color morphs. A couple other common names they are known by are Wimpel Moorii and Polli.
The Tropheus cichlids have a really interesting social structure that is built upon a colony of consistent tank mates. They are very active and have individual behaviors, ranging from curiosity about the goings on in the room to being very exuberant feeders. Feeding time can be very ‘wet’ for their keepers, but make this fish very fun and desirable.
A colony of 12 or more Poll’s Tropheus can make an active display and their personality is a definite plus. In the wild they are very aggressive with conspecifics, but are said to be less aggressive with other fish. In the aquarium their aggression level towards unrelated fish can vary depending on the personalities of the individual fish. However due to their very aggressive tendencies, they are best kept in a species specific tank. Do not add a new fish to an already established colony as this will cause an upset and death. They may also be kept in a larger aquarium with some other herbivorous rock dwelling African cichlids. The larger the tank and the more hiding places you have will help with aggression.
This hearty cichlid can be easy to moderate to keep as long as attention is paid to its diet and mandatory water changes are done, and difficult if they are neglected. Provide a sandy substrate, strong lighting to encourage algae growth, and several rock piles along with rocks formed into caves. Truly a rewarding fish for the aquarist who is willing to provide the necessary care.
For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care
- Kingdom: Animalia
- Phylum: Chordata
- Family: Cichlidae
- Genus: Tropheus
- Species: polli
- Aquarist Experience Level: Advanced
- Size of fish – inches: 6.5 inches (16.51 cm)
- Minimum Tank Size: 75 gal (284 L)
- Temperament: Aggressive
- Aquarium Hardiness: Moderately Difficult
- Temperature: 73.0 to 81.0° F (22.8 to 27.2° C)
- My Aquarium – Enter your aquarium to see if this fish is compatible!
Habitat: Distribution / Background
The Poll’s Tropheus Tropheus polli was described by G.S. (Glen S.) Axelrod in 1977. They are endemic to Lake Tanganyika, Africa. This species is listed on the IUCN Red list of Threatened Species as Vulnerable (VU) as they are exclusively known from only two locations in the Lake. They are found at Bula Point in the Kigoma district on the northwestern shore and on along the coast of the central eastern portion near the Kungwe Mountain range.
This fish is closely related to Tropheus annectens which is found on the western shores of the lake near Congonese. These two species behave similarly and it has been speculated they may be conspecifics. Other common names they are known by are Wimpel Moorii and Polli.
They inhabit rocky coastal areas at depths of 3 to 13 feet (1 – 4 m) =near the Kungwe Mountain range, and at Bula Point at depths of 20 to 60 feet (6.1 – 18 m). They are very specialized feeders which restricts their habitat to rocky areas with good algae growth. They are found over solid rock, interlocking rubble, or sandstone slabs but do not prefer loose rubble or sandy areas. The social groupings for this species has not yet been determined, but most Tropheus do not form schools. However they are generally found in groups and will form nuclear families, though not prolonged pairs as often found in other open water breeders.
The diet of Tropheus cichlids mostly consists of filamentous algae, but they also consume microorganisms. They are specialized aufwuchs feeders that spend much of their time searching and pecking at algae on the rocks. Aufwuchs refers to tough stringy algae that is attached to rocks. “Loose” Aufwuchs can contain insect larvae, nymphs, crustaceans, snails, mites and zooplankton.
- Scientific Name: Tropheus polli
- Social Grouping: Groups – Social groupings are not certain for this species, but generally Tropheus are found in groups and will form nuclear families, though not prolonged pairs as often found in other open water breeders.
- IUCN Red List: VU – Vulnerable
The Poll’s Tropheus is a moderately deep bodied fish that seems to have a larger head in proportion to its body and the body narrows as it forms the tail. It is distinguished from the other species in the Tropheus genus as it has a deeply forked caudal fin rather than the fan shaped fin found on the others. The caudal fin becomes even more deeply forked with age.
Cichlids have spiny rays in the back parts of the anal, dorsal, pectoral, and pelvic fins to help discourage predators. The front part of these fins are soft and perfect for precise positions and effortless movements in the water as opposed to fast swimming.
Cichlids also have one nostril on each side while other fish have 2 sets. To sense “smells” in the water, they suck water in and expel the water right back out after being “sampled” for a short or longer time, depending on how much the cichlid needs to “smell” the water. This feature is shared by saltwater damselfish and cichlids are thought to be closely related. All cichlids share a common feature that some saltwater fish such as wrasses and parrotfish have; a well-developed pharyngeal set of teeth that are in the throat, along with their regular teeth.
The body of a mature male is a slate gray or solid brown color while the female Poll’s Tropheus, and juveniles, will have light vertical striping. Like the Blue-Eyed Tropheus Tropheus brichardi, its eye is a bright turquoise in a well-maintained aquarium.
The Poll’s Tropheus will generally grow to a length of about 6 1/2 inches (16.5 cm). The Tropheus cichlids will generally live for about 5 – 8 years but have been know to live 10 years or more if well cared for.
- Size of fish – inches: 6.5 inches (16.51 cm) – This species can reach a length of 6 1/2″.
- Lifespan: 5 years – Tropheus cichlids generally live for 5 – 8 years, but may live 10 years or more with proper care.
Fish Keeping Difficulty
The Poll’s Tropheus are suggested for more experienced aquarists. The Tropheus cichlids are rather demanding to keep due to their susceptibility to certain infections of the intestinal tract such as “bloat.” They must have diligent attention given to their requirements of diet and habitat and they have a highly aggressive nature. They can be moderately easy to keep if it properly cared for, but difficult if not.
The aquarists must be willing to do frequent water changes and provide appropriate tank mates. They do best in a species tank, or if the aquarium is large enough they can be kept with other herbivorous types of cichlids.
- Aquarium Hardiness: Moderately Difficult
- Aquarist Experience Level: Advanced – These highly aggressive fish require attention to diet, diligent tank care, and are susceptible to “bloat” if stressed.
Foods and Feeding
The Poll’s Tropheus is an omnivore. but much of its diet consists of herbivorous foods. In the wild they are specialized aufwuchs feeders, aufwuchs which refers to tough stringy algae that is attached to rocks. They feed on algae scraped from the rocks along with microorganisms it contains.
In the aquarium they need to be fed a spirulina based flake and pellet. They should have spinach or romaine at least once a day. Only include foods that are high in fiber. If you use pellet, hold it underwater for a few moments before the fish eat it, that may prevent air released from the pellet from getting trapped in the belly. A small amount live foods can be offered occasionally as a treat. The best live protein supplements are Cyclops and Mysis, it is best to avoid soft or slimy foods as well as Tubifex, brine shrimp, beef heart, and mosquito larvae.
Feed proteins sparingly and avoid housing them with fish that need protein. Some aquarists say protein may cause bloat though others report no problems with it. Some have fed their fish frozen brine and plankton will no ill effects, while according to one author brine shrimp and insect larvae should be avoided. Stick with the same varieties of food and if you do switch, do it a little at a time, again because this may cause bloat. Rick Borstein, a writer on care of many cichlid fish, suggests HBH Graze and Dainichi Veggie Deluxe brand foods for the Tropheus. The ratios of vegetable matter in these products are good.
They have a long intestinal tract and should not be over fed, as overfeeding may contribute to bloat. Feed 3 times a day with small pinches of food instead of a large quantity once a day. This will keep the water quality higher over a longer time. All fish benefit from vitamins and supplements added to their foods. (See information about African Bloat in the table below.)
- Diet Type: Omnivore – Although these fish are omnivores, their diet consists primarily of herbivorous foods.
- Flake Food: Yes
- Tablet / Pellet: Yes
- Live foods (fishes, shrimps, worms): Some of Diet – Proteins should be fed sparingly.
- Vegetable Food: Most of Diet
- Meaty Food: Some of Diet – Proteins should be fed sparingly.
- Feeding Frequency: Several feedings per day – Generally feed 2-3 small feedings a day rather than a single large feeding for better water quality.
The Poll’s Tropheus needs diligent maintenance for good water quality. Regular partial water changes are very important and removing any uneaten foods will help prevent disease. Do water changes of 15% twice a week or 30% weekly, depending on stocking numbers.
The Lake Tanganyika cichlids cannot handle large water changes very well unless the new water chemistry closely matches the water they are in. If a large water change is needed, changing 15% every couple of days should bring water back to normal. This inability to tolerate large water changes is due to Lake Tanganyika being very deep and the water tends to stay stable.
- Water Changes: Weekly – Water changes of 15% twice a week or 30% weekly are recommended.
These are active swimmers that will utilize all areas of the tank, and they have an aggressive, territorial nature. A minimum 4 foot long, 75 gallon tank is suggested for an established adult group of 12 to 20, larger for more. They need good water movement along with very strong and efficient filtration. Lake Tanganyika is a very oxygen rich lake so bubblers need to be going day and night, even if there are plants. Regularly check nitrates and ph, nitrates should be no more than 25 ppm and a pH less than 7 is not tolerated. In addition keep an eye on total hardness and carbonate hardness. Avoid overfeeding and overstocking.
For Tropheus cichlids the water needs to be well buffered and maintained with small, regular water changes. They do fine in either freshwater or brackish freshwater. Salt is sometimes used as a buffering agent to increase the water’s carbonate hardness. An alternative buffering approach is to use a chemical filtration method, where the water passes through layers of crushed coral or coral sand.
Although rift lake cichlids need hard alkaline water they are not found in brackish waters. This cichlid has some salt tolerance so can be kept in slightly brackish water conditions. However it not suited to a full brackish water tank. Salinity must be less than about 10% of a normal saltwater tank, a specific gravity of less than 1.0002.
For freshwater an optional practice is to add 1 heaping teaspoon of salt per 11 gallons of water. This is considered to be a simple and natural remedy for wounds, minor fungal infections and film over the eyes of fish in transit. Tanganyika cichlids also need iodine for the thyroid to function properly to regulate growth and development, and which can be achieved by adding iodized table salt to the water. Be very careful to not add too much salt as this may cause bloat. Using a marine salt (used for salt water fish) will add some trace elements..
Provide a sandy or very small sized gravel substrate, strong lighting to encourage algae growth, and several rock piles with the rocks formed into caves. Plants may be included, which can help the fry have a higher survival rate, however these fish may eat them. Some hardy species include Swordplants that are the larger variety along with Anubias, Water Fern and Java Fern. These can be placed in the background or middle ground.
- Minimum Tank Size: 75 gal (284 L) – A tank that is 48″ long and about 75 gallons will be needed for a group.
- Suitable for Nano Tank: No
- Substrate Type: Sand/Gravel Mix
- Lighting Needs: Moderate – normal lighting – Normal lighting is okay, but stronger lighting will help with algae growth.
- Temperature: 73.0 to 81.0° F (22.8 to 27.2° C)
- Range ph: 8.0-9.5 – They can be adjusted closer to neutral if done slowly.
- Hardness Range: 10 – 15 dGH
- Brackish: Sometimes – Can tolerate a low salinity, but must be less than 10% of a normal saltwater tank, a specific gravity of less than 1.0002.
- Water Movement: Moderate
- Water Region: All – These fish will swim in all areas of the aquarium.
The Poll’s Tropheus are aggressive cichlids but do well in a properly set up species specific tank. They need to be kept in groups (community) of at least 12 or more, with one or two males in the group. Many females are needed to spread the aggression of the male. Do not add a new fish to an already established colony as this will cause an upset and death.
They may be kept in a larger aquarium with other herbivorous rock dwelling African cichlids. Some fish types, like the Sardine CichlidsCyprichromis leptosoma, Eretmodus species such as the Tanganyikan Goby CichlidEretmodus cyanostictus, and Upside-Down CatfishSynodontis species are known to have a calming affect on aggressive cichlids. If breeding them do not house with plecostomus as these fish will eat the fry at night.
Do not keep them with slow moving fish or carnivores. The Tropheus cichlids are voracious eaters that will eat anything that enters the tank, and will rarely let food get to the bottom. Providing more food in an attempt to feed the non-tropheus tank mates can cause the Tropheus cichlids to overeat, and that can lead to bloat. The larger the tank and the more hiding places you have (except when breeding), will help with aggression.
- Venomous: No
- Temperament: Aggressive
- Compatible with:
- Same species – conspecifics: Yes – Can be in groups of 12 or more, with 1 -2 males. Multiple females will help dilute the male’s aggressiveness.
- Peaceful fish (): Threat
- Semi-Aggressive (): Monitor – Other herbivorous Tanganyika cichlids fish can be kept if the tank is large enough with plenty of decor providing multiple hiding places.
- Aggressive (): Threat
- Large Semi-Aggressive (): Threat
- Large Aggressive, Predatory (): Threat
- Shrimps, Crabs, Snails: May be aggressive
- Plants: Monitor
Sex: Sexual differences
The sex of the Poll’s Tropheus is bit difficult to determine. Males have a more forked caudal fin than the females.
Breeding / Reproduction
The Poll’s Tropheus has been bred in captivity. Get a group of 12 to 20 juveniles for a 90 gallon tank and a harem should form. Do not add new individuals to an existing colony. A large numbers of females is needed for the best success. This keeps the aggression of the males divided and you are less likely to lose females. Females can be hard to bring into breeding condition. The male will always be ready to spawn and are constantly trying to coax the females to spawn whether they are ready or not.
The dominant male of the group will court a female and they will shimmy and circle one another. The female takes fertilized eggs into her mouth. She will carry them in her mouth, and when release will be healthy, large fry ready to feed. They can be fed crushed flake since they are pretty big when they are born. New moms tend to not be so successful with their first broods, so expect to lose the first sets of fry. The fry are 1/2″ (1.27 cm) when they are born, making them easy to feed. With in a week they are already scrapping with each other.
The adults in the community leave the fry alone if there are plenty of places to hide, but if you have other types of fish in the tank you may choose to remove the fry. They will breed about once a month. Breeding a wild caught specimen with captive bred fish helps to keep the lines healthier. See more information on breeding cichlids in: Breeding Freshwater Fish: Cichlids.
- Ease of Breeding: Moderate
Tropheus cichlids are relatively hardy as long as diligent attention is paid to maintaining their environment and diet. These fish are susceptible to typical fish ailments, especially if water is stale and of poor quality and has low oxygenation. An ounce of prevention is worth a pound of cure. Water changes, not overfeeding, providing adequate hiding places, and observation along with feeding your fish the proper foods will keep them in optimum health.
One common problem is Ich. It can be treated with the elevation of the tank temperature to 86° F (30° C) for 3 days. If that does not cure the Ich, then the fish needs to be treated with copper (remove any water conditioners). Several copper based fish medications are available for Ich. Copper use must be kept within the proper levels, so be sure to follow the manufacturers suggestions. You can also combine increasing the temperature with an Ich medication treatment. A copper test also can be used to keep the proper levels.
As with most fish they are susceptible to skin flukes and other parasitic infestations (protozoa, worms, etc.), fungal infections, and bacterial infections. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
|Dr. Jungle says…”What’s up with African Bloat or ‘Malawi Bloat’?”|
| The Tropheus species are very susceptible to African Bloat, also called Malawi Bloat. There seems to be no explainable rationale as to its cause. Though It is not certain what this disease is, it is generally believed to be caused by a protozoal parasite complicated by bacterial infection. The most common cause of this disease is stress and the first sign if illness is not eating. Stress can be caused by such things as transport, netting, poor water quality, insufficient diet, over feeding, and a lack of hiding places. Other causes, that are easily remedied, are an improper diet and adding too much salt to the water. The first sign of ‘bloat’ is loss of appetite which is then followed by swelling of the abdomen, labored breathing, listlessness, reclusiveness, possible red striations on the body, and stringy white feces. A fish that is not eating must be treated immediately or it can quickly become incurable and die. Prevention is of utmost importance, and It is possibly to cure a fish if treated right away. Following are some techniques aquarists use:|
The Poll’s Tropheus is only sometimes available online or in fish stores. It may be possible to special order them if you are willing to wait. Make sure you examine them for spinal defects before purchase.
- Animal-World References: Freshwater Fish and Plants
- Tropheus polli (Axelrod, 1977), Fishbase
- Tropheus polli, IUCN Red List of Threatened Species
- Dr. Rudiger Riehl and Hans A. Baensch, Aquarium Atlas Vol. 1, Publisher Hans A. Baensch, 1991
- Mark Phillip Smith, Lake Tanganyika Cichlids, A Complete Pet Owners Manual, 2nd Edition, Barron’s Educational Series, Inc. 2007
- George Zurlo, David Schleser, Cichlids (Complete Pet Owner’s Manual), Barron’s Education Series, 2005
- Glen S. Axelrod, Brian M. Scott, Neal Pronek, Encyclopedia Of Exotic Tropical Fishes For Freshwater Aquariums, TFH Publications, 2005
- Peter Bredell, Frank Schneidewind, Lake Tanganyika Cichlids, How to keep successfully and enjoy these exceptional fish, Interpet Publishing , 2002
- Paul V. Loiselle (1982), “African Dwarf Cichlids, the Lake Tanganyikan Species: Part One”, The Cichlid Room Companion, Ohio Cichlid Association
- Rhett Butler, “Cichlids – Lake Tanganyika”, Mongabay.com, Referenced online, 2007
- Glen S. Axelrod, Rift Lake Cichlids, T.F.H. Publications, Inc., 1979