Boitone's Pearlfish (Simpsonichthys boitonei) Care Guide
Simpsonichthys boitonei is a small annual killifish endemic to Brazil, living in seasonal pools of the upper Parana basin.
Compiled by Aquairi from published sources · Published · Updated
Overview
Simpsonichthys boitonei is a small annual killifish described by Carvalho in 1959 (formerly placed in Cynolebias). It is endemic to Brazil, where FishBase records it from the upper Parana River basin. As an annual species it completes its life cycle within a single rainy season, persisting through the dry period as drought-resistant eggs in the substrate.
Taxonomy
- Family: Rivulidae
- Genus: Simpsonichthys
- Scientific name: Simpsonichthys boitonei
- Former synonym: Cynolebias boitonei
Habitat
FishBase records the species from the upper Parana River basin in Brazil at roughly 15-16°S. As an annual killifish it occupies temporary freshwater bodies that fill during the rains and dry out seasonally, a habitat type characteristic of the Brazilian Cerrado.
Tank requirements
- Minimum tank volume: 30 L (about 8 gal)
- Temperature: 22-26 °C (72-79 °F); FishBase lists 20-24 °C
- pH: 6-7
- GH: 2-10 °dGH
- Lifespan: about 1 year (annual species)
Diet
The species is carnivorous and is best fed small live and frozen foods. In the aquarium it is generally fed twice daily. As a small killifish it favours items such as microworms, brine shrimp and similar small invertebrate fare.
Compatibility
FishBase describes it as a peaceful community fish. It is typically kept in a single-species harem of one male with several females. Robust or aggressive tankmates should be avoided given its small size and gentle temperament.
Breeding
FishBase describes the species as a bottom spawner with an incubation period of about two months. As an egg-burier, the eggs are deposited in the substrate and undergo a dry diapause, hatching when rewetted, which mirrors the seasonal drying of its natural pools.
Conservation status
IUCN Red List: FishBase cites Endangered, B1ab(iii,iv) (assessed 18 May 2022); Wikipedia references an older Vulnerable listing. The restricted Cerrado range makes the species sensitive to habitat loss.
Boitone's Pearlfish Breeding Guide
Overview
Simpsonichthys boitonei is a small Rivulidae killifish from the upper Parana River basin in Brazil. It is an annual species of seasonal pools and reaches about 5.5 cm total length. FishBase describes it as a bottom spawner with around two months of incubation and lists it as Endangered on the IUCN Red List.
Sexing
Males are the brightly coloured sex; females are plainer. A single male with one or two well-fed females makes a good spawning group, kept in their own breeding container rather than a community tank.
Conditioning
Tropical Fish Hobbyist advises isolating the breeders and preconditioning them with live or high-quality frozen foods for about a week before spawning to greatly raise the chance of success. The species is carnivorous.
Breeding Setup
Annual Simpsonichthys spawn into a soft substrate. Tropical Fish Hobbyist recommends a good grade of fertiliser-free peat moss or fibre, boiled briefly to sterilise it and ensure it sinks. The breeders are added over the settled peat and the container is covered. FishBase lists 20-24 C and notes aquarium conditions of about pH 6.6, hardness 6 and 24 C.
Spawning Behavior & Trigger
The pair dives into the peat to spawn, burying eggs within it. Tropical Fish Hobbyist reports that the female generally releases her full complement of eggs within about eight hours, and at most around twenty-four hours. After spawning the peat is poured through a fine net to capture the egg-bearing medium.
Egg Diapause & Hatching
The peat is squeezed dry, rolled in newspaper and dried until pinching it yields no water, then stored at room temperature. Annual eggs pass through several diapause periods before hatching. Tropical Fish Hobbyist gives an incubation range of roughly two to six months depending on species and storage temperature, consistent with the two months FishBase cites for this species. The peat is then wetted with soft water; ready eggs hatch within about 24 hours, sometimes sooner.
Common Challenges
Diapause timing and peat moisture are the main hurdles, as with all annuals. Because the species completes its life cycle within a year and is of conservation concern, maintaining a continuous breeding line is important for keeping captive stock going.