Thorichthys passionis

Black-chin cichlid

Scientific Classification

Kingdom:

Animalia

Phylum:

Chordata

Class:

Actinopterygii

Order:

Cichliformes

Family:

Cichlidae

Genus:

Thorichthys

Species:

passionis

IUCN Status:

Vulnerable

Origin

Continent:

Central America

Quick Stats

Difficulty:

Easy

Environment:

Freshwater

Temperature:

20-32°C

pH Level:

6.5 - 8.5

Water Hardness:

36 - 268 ppm

Lifespan:

10 years

Adult Size:

8-15cm

Diet:

Omnivore

Creature Type:

Fish

TDS:

250 ppm

Water Flow:

Low Flow

Aquarium Building Information

Minimum Tank Size:

200L

Swimming Zone:

middle, bottom

Oxygen Consumption:

Medium

Waste Production:

Medium

Metabolism Rate:

Medium

Activity Level:

Moderate

Feeding Frequency:

Daily

Food Types:

Sinking Pellets, Flakes, Frozen Food, Live Food, Vegetables

About This Species

Basic Description

The Black-chin cichlid, also known as the Passionis cichlid, is a vibrant freshwater fish from Central America that brings moderate activity to an aquarium. This species is best suited for aquarists with some prior experience due to its specific needs and temperament. As an omnivore, it is not a picky eater and will readily accept a variety of prepared foods like sinking pellets and flakes, as well as frozen, live, and vegetable-based meals. It has a long lifespan, often living for a decade or more with proper care. In an aquarium, it typically occupies the middle and bottom levels, where it will spend time exploring and sifting through the substrate. This natural digging behavior means they can uproot delicate plants, so durable aquarium decor and hardy plants are recommended. They are known to be territorial fish and are best kept as a bonded pair rather than in large groups. Before deciding to keep this fish, it is important to have a spacious tank ready to accommodate its adult size and provide enough room for it to establish its own territory.

Detailed Description

Native to the slow-moving, hard, and alkaline waters of Mexico and Guatemala, the Black-chin cichlid is a fascinating species for the dedicated hobbyist. To thrive in captivity, its aquarium must replicate these conditions. A large tank is essential, not only to accommodate its considerable adult size but also to manage its territorial nature. The ideal setup should feature a fine sand or smooth gravel substrate to facilitate its natural digging behavior without causing injury. This species is a known plant rooter, so robust plants like Anubias or Java Fern attached to driftwood are preferable to delicate, rooted varieties. Rockwork, caves, and driftwood should be used to create visual barriers and distinct territories, which is crucial for mitigating aggression, especially if kept with other fish. As a pair-forming cichlid, it is best to acquire a compatible pair, which often involves raising a group of juveniles together and allowing them to select their own mates. Due to its medium waste production and sensitivity to pollutants, a powerful and efficient filtration system is required, though the water outflow should be gentle to mimic its native low-flow environment. Regular and consistent water changes are paramount to keeping nitrate levels low and maintaining the stable, hard, and alkaline water chemistry it requires. Its omnivorous diet should be varied to ensure optimal health. A high-quality sinking cichlid pellet can serve as a staple, supplemented regularly with protein-rich frozen or live foods and vegetable matter. Its social behavior is centered on its territory, which it will actively defend, particularly during breeding. Tankmates must be chosen with care; they should be robust, of similar size, and able to hold their own without being overly aggressive. Fish that occupy the upper water column are often a good choice.

Scientific Description

Thorichthys passionis is a freshwater species belonging to the Cichlidae family, endemic to specific river drainages in Mexico and Guatemala. Like other members of the Thorichthys genus, it exhibits a laterally compressed, or compressiform, body shape, which is an adaptation for maneuverability in habitats with complex structures. It occupies an ecological niche in slow-moving, alkaline freshwater environments characterized by high mineral content. As an omnivorous benthic feeder, T. passionis plays a role in bioturbation. It sifts through the substrate to forage for invertebrates, algae, and detritus, which helps aerate the sediment and cycle nutrients within its ecosystem. This species exhibits a distinct pair-bonding social structure, a common reproductive strategy among Neotropical cichlids. Intraspecific communication is highly developed, featuring complex visual displays involving its bright coloration. These displays are integral to territorial disputes and courtship rituals. Its metabolism, oxygen consumption, and waste production are categorized as medium, aligning with its moderate activity level and feeding habits. In a closed system like an aquarium, these physiological traits result in a moderate bioload. Unfortunately, Thorichthys passionis is listed as Vulnerable on the IUCN Red List of Threatened Species. This conservation status highlights significant threats to its wild populations, likely stemming from habitat degradation, water pollution, and the introduction of non-native species. The vulnerability of its wild populations underscores the importance of sustainable aquarium trade practices and the potential role of captive breeding efforts in conservation.

Breeding Description

Breeding Thorichthys passionis is considered moderately difficult, with the primary challenge often being the establishment of a compatible, bonded pair. This species is monogamous and exhibits strong pair-bonding behavior. The most reliable method for obtaining a pair is to purchase a group of six to eight juveniles and raise them in a spacious tank, allowing them to pair off naturally. Once a pair has formed, they will often separate from the group and defend a shared territory. At this point, it is safest to remove the other fish to prevent aggression. Sexing individuals can be challenging, especially when they are young. Generally, mature males are larger, exhibit more intense coloration, and often develop elongated, more pointed dorsal and anal fins. Females tend to be smaller and have a rounder body shape, particularly when gravid. To encourage spawning, condition the pair with a diet rich in live and frozen foods. Maintaining pristine water quality with stable, warm temperatures at the higher end of their acceptable range can also trigger reproductive behavior. As substrate spawners, the pair will choose a flat, clean surface such as a smooth rock, slate, or a piece of driftwood for egg-laying. They will meticulously clean the site before the female deposits rows of adhesive eggs, which the male follows behind to fertilize. This species provides excellent biparental care. Both male and female will guard the eggs vigorously, fanning them to ensure oxygenation and removing any unfertilized eggs. After a few days, the eggs will hatch, and the parents will move the wriggling fry into pre-dug pits in the substrate for continued protection. Once the fry become free-swimming, they can be fed with infusoria, newly hatched brine shrimp, or finely crushed high-protein flake food. The parents will diligently guard their school of fry for several weeks, guiding them around the tank to forage. A dedicated breeding aquarium is highly recommended to maximize fry survival and manage the heightened territorial aggression of the parents.