Firemouth Cichlid Thorichthys meeki: A Complete Care Guide

The Firemouth Cichlid, also known as the Firemouth fish (Thorichthys meeki), is a popular freshwater aquarium fish among aquarists. Native to Central America, these fish thrive in slow-moving waters such as rivers and lagoons in Mexico, Belize, and Guatemala.

In this article, we will dive into the world of Firemouth Cichlids, covering their care, diet, breeding, compatibility, size, tank size, male vs. female comparison, and lifespan.

Firemouth Cichlid Taxonomy

• Kingdom: Animalia
• Phylum: Chordata
• Class: Actinopterygii
• Order: Perciformes
• Family: Cichlidae
• Subfamily: Cichlasomatinae
• Genus: Thorichthys
• Species: Thorichthys meeki (Brind, 1918)
• Synonyms: Cichlasoma meeki, Cichlasoma hyorhynchum, Herichthys meeki, Thorichthys helleri meeki
• Common names in Spanish: Cíclido boca de fuego, Mojarra boca de fuego, Boca de Fuego, torito, Chanchito escarlata, cacharrita ojo pelado.
• Common names in English: Firemouth, redbreasted cichlid, Firemouth meeki, Firemouth Cichlid, Firemouth Fish, firemouth cichlid fish, meeki cichlid.

Nam y Rhee (2022) report the complete mitochondrial genome of the Firemouth Cichlid, Thorichthys meeki, and found that the gene order of T. meeki’s mitogenome was identical to that of other cichlid species, while a phylogenetic tree showed a close relationship of T. meeki with Thorichthys aureus (Gunther 1862) within the Heroini tribe.

Appearance and Size of Firemouth Cichlids

Firemouth Cichlids are named for the intense red coloration of their throats, especially prominent in males. These fish can grow on average up to about 8 cm (females) and 12 cm (males); however, specimens up to 17 cm in length have been reported in their natural habitat.

Male Firemouth Cichlids are slightly larger and have more vivid coloration than females. Males also tend to have longer fins, while females have rounder bellies.

The Firemouth Cichlid has an oval, laterally compressed body, with a large head and prominent mouth.

Coloration

The most distinctive feature of this species is its coloration, which ranges from reddish and orange tones to olive greens, depending on mood and environmental conditions. Beeching y Pike (2010) reported that Thorichthys meeki, from hatching to 205 days old, exhibits 16 dynamic color pattern elements, and that changes in color patterns were correlated with age and body size.

According to CABI (2017), Firemouth fishes are characterized by the bright red or orange coloration on the lower part of their heads; the fish’s bodies have 5 or 6 vertical black bars of varying intensity along the flanks, and all fins, except the pectorals, have a red border with rows of blue iridescent spots or dots.

Additionally, Beeching et al., (2013) determined the histological basis of two melanistic color pattern elements in the integument of Firemouth Cichlids, Thorichthys meeki; according to the researchers, the vertical bars on the flanks were formed by three layers of dermal melanophores, while the opercular spots were formed by four layers (two lateral and two medial) in the integument surrounding the opercular bones.

On the other hand, males are generally larger and exhibit more intense colors, especially during the breeding season. Females are typically smaller and display duller colors.

Lifespan

With proper care, Firemouth Cichlids can live around 10 years. In some cases, they can even reach 15 years in captivity. Ensuring high water quality conditions and a balanced diet is essential to prolong their lifespan.

Natural Habitat

The Firemouth Cichlid is native to the waters of the Atlantic basin in Mexico, Belize, and Guatemala. However, it has been introduced to Colombia, the U.S., the Philippines, Singapore, Israel, and Australia.

In their natural habitat, Firemouth Cichlids inhabit clear, slightly acidic rivers and lakes with abundant aquatic vegetation. These habitats are typically lentic or slow-flowing, relatively shallow (depth <1.5 meters), turbid, and with a soft or muddy substrate covered with leaf litter and submerged branches (CABI, 2017).

Care Requirements for Firemouth Cichlids

For a single Firemouth Cichlid, a minimum tank size of 30 gallons is recommended, although larger tanks (up to 50 gallons) are better if you plan to keep more than one fish. These cichlids require plenty of swimming space but also need hiding spots like rocks, driftwood, or caves to establish their territory. Their natural habitat is murky, slow-moving water, so dim lighting and soft substrates such as sand will help replicate their environment.

Regular water changes (about 25-30% weekly) and a good filtration system are crucial to maintaining water quality. Ideal water parameters include:

Table 01. Water quality parameters for breeding Firemouth Cichlids (Thorichthys meeki).

On the other hand, experts recommend including a sandy or gravel substrate in breeding aquariums, as Firemouth Cichlids are prone to digging.

Firemouth Cichlid Diet

Firemouth Cichlids are omnivores and are not picky eaters. In the wild, they feed on small crustaceans, larvae, and plant matter. Valtierra-Vega y Schmitter-Soto (2000) report that in their natural habitat in Mexico, T. meeki predominantly consumed cladocerans and copepods (the harpacticoids: Eucyclops agilis, Macrocyclops albidus, and Mesocyclops longisetus), both in abundance and frequency.

In captivity, their diet should consist of high-quality flakes or pellets, supplemented with live or frozen foods such as brine shrimp (Artemia) and bloodworms. To keep them healthy, feed them smaller portions two or three times a day.

Additionally, it is important to provide the fish with sufficient carotenoids in their diet to maintain their coloration. Fauque (2015) demonstrated that a diet low in carotenoids is enough to reduce the redness in male Thorichthys meeki, while females respond differently.

Compatibility and Tank Mates

While generally peaceful, Firemouth Cichlids can become territorial, particularly during breeding. They form monogamous pairs and defend a territory around their nest.

Firemouth Cichlids get along well with other peaceful species, but it’s best to avoid aggressive or highly territorial fish.

Suitable tank mates include:

• Corydoras catfish
• Plecos
• Dwarf gouramis
• Swordtails
• Rainbowfish

Be cautious when introducing other cichlids, as they may trigger aggressive behavior, especially during spawning.

Breeding

Firemouth Cichlids are relatively easy to breed in captivity. The male and female Firemouth Cichlid (Thorichthys meeki) develop red ventral coloration at sexual maturity, along with temporally variable black (melanic) elements (Beeching 2017).

Male vs. Female

The main differences between male and female Firemouth Cichlids lie in their size, coloration, and fins. Males are generally larger, have longer fins, and display more intense red coloration on their throats, especially during breeding displays. Females are smaller, with a rounder belly.

They form monogamous pairs and typically lay eggs on flat surfaces such as rocks or leaves. During breeding, males become more aggressive as they defend the territory. If you are interested in breeding, consider setting up a breeding tank to protect the fry once the eggs hatch.

Once the pair forms, the fish will build a nest in a depression in the substrate or on a flat surface. The female will lay hundreds of eggs, which will be fertilized by the male. Both parents will care for the eggs and fry until they become independent.

Embryonic and Larval Development

Gültekín y Yilmaz (2023) investigated the embryonic and larval development of the Firemouth Cichlid (Thorichthys meeki) and reported the following:

• Spawning and embryonic development occurred at an average water temperature of 27°C.

• Ovulation lasted approximately 60 minutes, and the average number of eggs was 1,159. The long axis of the egg measured an average of 1.47 ± 0.01 mm, and the short axis averaged 1.14 ± 0.01 mm.

• Incubation took place between 38.20 and 51.55 hours.

• The average total length of newly hatched larvae was measured at 3.38 ± 0.03 mm. The larvae begin swimming on the fifth day and start feeding by consuming the yolk sac on the eighth day.

• The larvae reached the appearance of an adult by the end of day 30, and the average total length of the larvae was measured at 11.02 ± 0.36 mm on day 30.

Common Health Issues

Firemouth Cichlids are hardy, but like all aquarium fish, they are susceptible to diseases such as Ich (white spot disease) and Head and Lateral Line Erosion (HLLE). These issues can be prevented with regular aquarium maintenance and ensuring proper water quality.

Additionally, López-Segovia et al., (2024) reported a rare disease known as “saddleback syndrome” in wild specimens of the Firemouth Cichlid. This condition is characterized by abnormalities in the shape, number, or absence of dorsal pterygiophores, causing a concavity in the dorsal region and missing sections of the fins.

Conclusion

The Firemouth Cichlid is a great choice for both beginners and experienced aquarists, offering a balance between beauty and relatively simple care. With its striking appearance, straightforward breeding process, and long lifespan, they can be a rewarding addition to any aquarium. Just make sure your tank is set up to mimic their natural environment, with plenty of hiding places, proper water conditions, and a balanced diet.

References

Beeching, S. C., & Pike, R. E. (2010). Ontogenetic color change in the Firemouth Cichlid, Thorichthys meeki. Copeia, 2010(2), 189-195.

Beeching, S. C., Glass, B. A., & Rehorek, S. J. (2013). Histology of melanic flank and opercular color pattern elements in the firemouth cichlid, Thorichthys meeki. Journal of Morphology, 274(7), 743-749. https://doi.org/10.1002/jmor.20131

Beeching, S.C. Investigating the behavioral significance of color pattern in a cichlid fish: firemouths Thorichthys meeki respond differently to color-manipulated video and dummy conspecifics. Ichthyol Res 64, 301–307 (2017). https://doi.org/10.1007/s10228-016-0567-y

CABI. 2017. Thorichthys meeki (firemouth cichlid) [original text by anonymous]. In Invasive Species Compendium. CAB International, Wallingford, U.K. Available:

Fauque, Sarah Anne, “Dietary carotenoids and the complex role of redness in the behavior of the firemouth cichlid Thorichthys meeki.” (2015). Electronic Theses and Dissertations. Paper 2334. https://doi.org/10.18297/etd/2334

GÜLTEKIN, H., & YILMAZ, E. (2023). FIRE MOUTH CHICHLID (Thorichthys meeki Brind, 1918) EMBRYONIC AND LARVAL DEVELOPMENT. AQUATIC ANIMAL REPORTS (AQAR), 1(2), 65–81. https://doi.org/10.5281/zenodo.8229232

López-Segovia, E., Del Moral-Flores, L. F., Wakida-Kusunoki, A., & Pérez-Díaz, J. (2024). Saddleback syndrome in the firemouth cichlid Thorichthys meeki (Cichliformes: Cichlidae) in Campeche, Mexico. Proceedings of the Zoological Institute RAS, 328(1), 66-75.

Nam, S. E., & Rhee, J. S. (2022). Characterization and phylogenetic analysis of the complete mitochondrial genome of the firemouth cichlid, Thorichthys meeki (Perciformes: Cichlidae). Mitochondrial DNA Part B, 7(6), 1072–1074. https://doi.org/10.1080/23802359.2022.2086080

Valtierra-Vega, M. T., & Schmitter-Soto, J. J. (2000). Hábitos alimentarios de las mojarras (Perciformes: Cichlidae) de la laguna Caobas, Quintana Roo, México. Revista de Biología Tropical, 48(2-3), 503-508.