Thorichthys pasionis Breeding Guide
How to breed Thorichthys pasionis: a biparental substrate-spawning Central American cichlid that deposits eggs in batches on a cleaned surface.
Overview
Thorichthys pasionis is a Central American cichlid distributed in Mexico and Guatemala, in rivers flowing into the Gulf of Mexico from the Grijalva to the Candelaria, where it favours slow-flowing lower reaches and lagoons. It is a relative of the firemouth and breeds as a biparental substrate spawner. According to AquaInfo it is considered easy to breed in the aquarium.
Sexing
Males reach substantially larger sizes than females, attaining up to about 17 cm, while females stay noticeably smaller. Females in breeding condition appear more rounded; both sexes adopt a contrasting barred spawning pattern as the pair forms.
Conditioning
Mature pairs typically form during the warmer, lower-flow period of the year, and the species is monogamous. Maintaining clean, warm water and a varied diet supports condition. Reported breeding parameters are a temperature of 25-30 C (minimum about 25 C), pH 7.5-9.0 with alkaline water preferred, and hardness around 5-15 dGH.
Breeding Setup
- Provide a flat, smooth horizontal or slightly sloping surface in a sheltered spot for egg deposition.
- Flower pots are readily accepted; the species also accepts vertical surfaces.
- Use sand substrate so the pair can excavate nursery pits.
- A minimum tank of around 200 L suits a pair of this size.
Spawning Behavior & Trigger
The female deposits eggs in small batches; after each batch the male passes over to release milt, and the sequence repeats. Eggs are placed a little apart rather than in a dense cluster, an adaptation linked to oxygen-poor water. Adult pairs can produce over five hundred eggs, with reported clutches of roughly 100-500.
Egg & Fry Care
Eggs are yellowish, adhesive and small (to about 1.7 mm) and hatch within roughly 72 hours. The parents move the larvae to a pre-dug pit in the substrate while they absorb their yolk sacs, and the pair provides extended care of the free-swimming fry.
Common Challenges
As with related firemouth-type cichlids, pairs become territorial during breeding and may turn on tankmates or each other; provide line-of-sight breaks and monitor the pair. First spawns from young fish are often smaller and may be eaten before the pair settles into reliable parental behaviour.