Moderate
Gunther's Nothobranch (Nothobranchius guentheri)
22–26°C · pH 6–7.5 · 40L
£11.99
Brazilian annual killifish supplied at 2.5-4 cm. Best in a covered species setup at 20-23 C with soft, clean water and peat or coir spawning media.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Nematolebias whitei
White's Cynolebias / Rio Pearlfish bond and breed in male/female pairs. Buying a pair gives them the social structure they need — and you get a better price per fish.
Brazilian annual killifish supplied at 2.5-4 cm. Best in a covered species setup at 20-23 C with soft, clean water and peat or coir spawning media.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Maintain these water conditions for optimal health and vibrant colors
White's Cynolebias, also known as the Rio Pearlfish, is a specialist Brazilian annual killifish currently listed as Nematolebias whitei. Older trade and supplier data may still use Cynolebias whitei, so that name is kept here as synonym context rather than pushed into the title or repeated as a keyword. This listing is for fish supplied around 2.5-4 cm when available.
This is the kind of fish that rewards a keeper who enjoys behaviour, biology and careful observation. It is not a generic warm community fish. It comes from seasonal pools that can dry out, so the adult fish live fast, feed hard and spawn into soft substrate while the eggs survive the dry period. The appeal is the whole story: pearly males, smaller patterned females, soft-water specialist care and a breeding method that feels very different from ordinary aquarium fish.
Males are the display fish, with a tapered body, strong finnage and pearly spotting that can shimmer across the body and fins. The exact colour varies with mood, age, light and condition. A settled male over a darker base can show a soft metallic sheen with warm red, green or blue highlights, while a stressed or subordinate fish may look much plainer. Females are smaller and more subdued, usually brownish with darker spotting and shorter rounded fins.
Subdued light, floating cover and a darker base help this fish look its best. The verified Petra source photo is preserved for this SKU, and the existing AI/gallery images are kept as additional visual context rather than being removed. Alt text is being cleaned so it describes the fish instead of repeating search phrases.
FishBase places Nematolebias whitei in the Laguna de Araruama basin, the Das Ostras River basin and coastal plains near the mouth of the Sao Joao River in Rio de Janeiro State, Brazil. The species lives in small temporary freshwater pools on floodplains of streams and lagoons. These pools are shallow, muddy and seasonal, and the dry periods can remove the adult fish from the habitat entirely.
That explains the annual life cycle. Adults spawn into the substrate, the eggs enter diapause in the mud, and hatching follows when water returns. Aquarium keepers should respect that biology rather than treating the fish as a long-lived community species. A well-kept group can be fascinating, but continuity usually depends on collecting and incubating eggs.
Use a secure, covered aquarium with gentle filtration and calm water. A sponge filter or guarded low-flow filter is ideal. The lid matters because killifish can jump, especially during feeding, chasing or water-change disturbance. Floating plants, Java moss, leaf litter and shaded areas all help the fish settle.
For display, fine sand with a removable spawning container is often easier than a full peat base. For breeding, provide a deep container of prepared peat moss or coir so the pair can dive and deposit eggs. Keep the medium removable because annual-killifish eggs are normally stored moist outside the aquarium for an incubation period before being re-flooded.
Keep the tank clean without making it harsh. These fish enjoy rich foods, but rich food in a small aquarium can spoil the water quickly. Feed well, remove leftovers and use regular small water changes. Stable clean water is more important than chasing a dramatic blackwater look.
Nematolebias whitei is a carnivorous micro-predator. Daphnia, brine shrimp, mosquito larvae, bloodworm, whiteworm, grindal worm and similar small foods are all useful. BKA notes that dried foods are seldom taken by this species, so do not buy it expecting ordinary dry food to be enough.
Feed little and often while keeping water quality high. Good food brings better colour, growth and spawning condition, but overfeeding can cause trouble. Watch the fish eat, remove leftovers and vary the diet rather than relying on one food.
Although this fish can look calm outside spawning, it should not be treated as a simple peaceful community choice. FishBase describes males as territorial and very aggressive during courtship and spawning, and the safer aquarium recommendation is a species-focused setup. A pair or one male with two females is usually a better starting point than several males in a small tank.
Avoid warm busy community tanks, fin nippers, aggressive fish, fast feeders and anything large enough to intimidate them. Tiny shrimp and fry may also be eaten. If any tank mates are attempted, they should be very calm, similar-sized fish that share the same soft-water conditions, but a species tank remains the best route for behaviour, feeding and breeding.
White's Cynolebias is an annual bottom-spawning killifish. Condition the pair with live and frozen foods, then offer peat or coir in a container deep enough for proper diving behaviour. FishBase records bottom spawning and a four-month incubation reference; breeder reports vary, so treat incubation as a monitored process rather than a fixed calendar.
The storage medium should stay moist, not flooded and not bone dry. Fry need very small foods, frequent feeding and clean water. Killi.co.uk breeder reports describe peat spawning, mostly soft and acidic water, and rapid fry growth. This is one of the more approachable South American annuals, but it still needs a keeper willing to manage eggs rather than simply hoping adults live for years.
This livestock listing is suitable for keepers who can provide a covered specialist aquarium, soft clean water, small live or frozen foods and a plan for the short annual life cycle. Tropical Fish Co uses licensed live-animal courier services for eligible livestock and backs live fish with our Live Arrival Guarantee, subject to the current delivery terms at checkout.
If you want a colourful, unusual annual killifish with a real breeding story, White's Cynolebias is a strong choice. If you want a long-lived, low-maintenance community fish for a warm mixed tank, choose a different species.
22–26°C · pH 6–7.5 · 40L
20–26°C · pH 6–7.5 · 40L
20–24°C · pH 6–7.5 · 40L
23–25°C · pH 8–8.5 · 180L
22–28°C · pH 5.5–7.2 · 25L
18–26°C · pH 6.5–8 · 30L
23–27°C · pH 7.4–8.4 · 500L
20–27°C · pH 6–7 · 54L
23–27°C · pH 7.4–8.4 · 150L
24–28°C · pH 6.5–7.8 · 300L
20–24°C · pH 7–8 · 45L
24–28°C · pH 6.5–7.5 · 2000L
24–28°C · pH 7.5–8.5 · 200L
24–28°C · pH 5.5–7 · 60L
18–25°C · pH 6–8 · 100L
24–28°C · pH 7–8 · 120L
18–28°C · pH 6.5–8 · 20L
24–27°C · pH 7.5–8.8 · 150L
22–26°C · pH 6–7.5 · 60L
24–28°C · pH 7.5–8.5 · 40L
24–28°C · pH 7.5–8.5 · 500L