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Written by: Dan Colodney

Thorichthys pasionis - Blackgullet cichlid

Thorichthys pasionis point map


Thorichthys pasionis



One of my favorite cichlids, T. pasionis is surely one of the most beautiful to inhabit the rivers and lagoons of lowlands of the Atlantic Slope in Central America. Though the best known Thorichthy is undoubtedly meeki, the "firemouth cichlid', T. pasioinis, sometime referred to as the "yellow meeki" deserves more recognition. First defined by Luis Rene Rivas in 1962 from specimens collected from Rio De la Pasion at Sayaxche in northern Guatamala during an expedition conducted in June of 1961, it has been only within the past 10 years that this beautiful little cichlid has become 'known' in the hobby.

For the taxonomists among you, pasionis is found to have an elevated number of gill rakers relative to the other species of the genus, and by the absence of supplementary lateral lines on the caudal fin, more numerous pectoral rays and a longer anal base relative to T. aureus, T. helleri and T. maculipinnis.

In its native habitat, Thorichthys pasionis is always found with T. meeki, as it inhabits a great part of the latters range; Differences in coloration are striking however. As opposed to the grey body and red gill covers of meeki, T. pasionis exhibits a green-yellow overall body color, a more pointed frontal profile, a high dorsal fin with elongated extensions and most notably, a brilliant yellow gill cover with black border and gular pouch with distinct 'eye spot'..

Thorichthys pasionis

Thorichthys pasionis is most commonly found in lagoons with soft, muddy bottoms and low visibility. The chemistry of the water is typically alkaline, with a pH ranging from 7.5-8.5 and while hardness is variable, it's usually 8° GH or higher. Water temperature ranges from 77° - 86°F.

Thorichthys pasionis exists in complex communities with very high density which include cichlids such as Thorichthys meeki, Amphilophus robertsoni, Paratheraps bifasciatus, Archocentrus octofaciatum, Parachromis freidrichsthali, Petenia splendida and other 'cichlasomines' including salvini, urophthalmus, heterospilum and pearsei. Also found are numerous non-cichlid fishes which can include Poecilidae (petenense), Gambusia (sexradiata), Astynax (aeneus), Lepisosteidae (L. tropicus), Pimelodidae (Rhamdia guatemalensis), Atherinidae (Atherinalla alvarezi) and Symbranchidae (Ophiossternon aenigmaticum).

Pasionis pairs stake out a territory using any object as deliniation and guarded areas may be as small as ten inches square. There's a high degree of interraction among paired and non-paired fishes but significant aggression is rare and mostly limited to short frontal runs and 'face-offs' in which individuals extend gill covers and gular pouches in an attempt to intimidate each other. After a brief advance, a pair retreats and then repeats the process several times before withdrawing to its territory. In this regard, pasionis exhibits interactive behaviour much like its cousin T. meeki.

Juveniles and non-breeding individuals will be found gathered among driftwood on the substrate, picking through bottom debris in search of food. In this regard, they are much like the South American Geo and Gymnogeophagine 'sifters', in that mouthfulls of debris are picked up, any food particles 'eaten' and non-edible material expelled through the gill rakers. Though i've read no articles in which analyses of stomach contents are mentioned, it seems reasonable to assume that the diet of T. pasionis consists of invertebrate organisms found in the first several millimeters of upper layer substrate. Note that no plant material is found in this layer indicating that pasionis' diet is totally absent of vegetable matter.

In the aquarium, T. pasionis males grow to about 6 inches SL while females are smaller at about 4 inches. There is little sexual dimorphism in this species; though females will sometimes exhibit a less striking yellow color over the front flanks, as well as shorter fin filaments, these differences are rarely significant. In breeding coloration, the yellow color is intensified in both males and females and distinct black bars will be noted on the sides. The gular pouches exhibit a deepening of the normal black color, giving the fish an intense black and yellow overall appearance.

Spawning pairs seem to prefer vertical surfaces or small crevices in which to place their yellow, adhesive eggs. These are quite small with a maximum size of only 1.7 mm and placed with space between them, these characteristics presumably a throw-back to the low oxygen, high sediment habitat in which these cichlids are found. Each successful spawn produces about 300 eggs which hatch in about 2 days at 78°F, and fry are free swimming in five days thereafter. As with many cichlid species, the fry will be taken into the parents mouth and moved to small pre-dug pits throughout the substrate. In this regard, sand is the ideal substrate for T. pasionis since it allows for these pits to be successfully excavated. In the absense of a suitable substrate (large sized pea gravel for example), experience indicates that these cichlids will clean an entire ten inch square area of the bottom and place the fry directly on the glass. This seems to cause some stress in both fry and adults and numbers of resulting juveniles will be reduced, sometimes significantly. Generally, it's the female that takes care of both eggs and fry though the male will not be found far away, guarding the spawning site and driving off any potential intruders. As with almost all cichlids, the female will 'fan' both the eggs and subsequent wrigglers with pectoral fins to keep silt and debris off them and to elevate oxygen levels in the microhabitat surrounding the eggs.

This is not a difficult cichlid to keep. It's requirements are easily met by any cichlid hobbyist with at least a 55 gallon tank, though my preference is for 75 gallons. This allows for maintaining T. pasionis in groups of 8 or more, which seems in my experience to produce the best results and allow for the full range of behaviours. Note that this is a shy and not very active cichlid, preferring to remain within its territory in the lower 8-10 inches of the water column. Tankmates, chosen carefully, can help to bring about a more active behaviour. I'd recommend Poecilia petenense which is virtually ignored by T. pasionis and is peaceful enough to return the favor. Too, they are large enough to withstand the minor attacks of a breeding pair of pasionis. Other examples of syntopic 'dithers' which do well in a pasionis tank include Rhamdia species and Astyanax aeneus. You might also consider fishes that are not found in pasionis' native habitat such as rainbows. T. pasionis does not do well under bright light and in fact, I leave the lights off over my pasionis tank all the time.

T. pasionis is definitely not a picky eater. Anything you drop in the tank is fair game though I strive to use 'live' foods when possible and lots of carotene rich krill to enhance the yellow colors which are so outstanding in this spsecies. Given the relative ease of maintainance I can highly recommend Thorichthys pasionis to the commited cichlid hobbyist.

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