Magnificent Killifish (Hypsolebias magnificus) Pair

Common Name

Magnificus Killifish. Often sold in pairs since one male with one or more females is the preferred setup for breeding and display.

Origin and Habitat

Endemic to Brazil in the middle São Francisco River basin within the Caatinga region. In nature this species lives in seasonal pools and marshy depressions that fill during the rainy season and shrink or dry through the year. Water is warm and still to very slow with a soft sandy or muddy bottom, leaf litter, and overhanging shrubs that shade the surface. These pools are shallow and nutrient rich after rains, which drives bursts of invertebrate life.

Temperature and Water Conditions

A practical aquarium range is 22 to 26°C, which is 71 to 79°F. Many aquarists keep this species near neutral to slightly acidic water, commonly around pH 6.5 to 7.5 with soft to moderate hardness. We do not recommend chasing or altering numbers except for special breeding situations. Stable conditions, gentle filtration, and very low nitrogen waste matter far more than exact values. Use a tight fitting lid since annual killifish are skilled jumpers.

Appearance and Size

Males carry the show with metallic blues and greens over a dark base, bold fin patterning, and bright edging. Females are smaller and subtler in tan and olive with soft spots and bars that blend into leaf litter. Adult size is about 5 cm total length, which is about 2 inches.

Diet in the Wild

A micro predator that feeds on insect larvae, tiny crustaceans, and other aquatic invertebrates that bloom in temporary waters after rains. Rapid feeding and fast growth match the short seasonal window.

Feeding in Captivity

Offer small live or frozen foods such as baby brine shrimp, daphnia, cyclops, blackworms, and mosquito larvae. Many fish learn to accept high quality micro pellets if you mix them with thawed frozen food and slowly reduce the frozen portion. Several small meals each day produce better condition and color than a single large feeding.

Behavior and Tank Setup

Generally peaceful with fish of similar size. Males may spar during courtship. For display, a planted nano to small tank with botanicals, leaf litter, and gentle flow works very well. For breeding, keep one male with one to three females. Provide soft fine substrate zones and a sponge filter for circulation. Dim light and floating cover help fish feel secure and deepen color.

Breeding and Egg Incubation

This is an annual substrate spawner. In nature the pair buries eggs in soft bottom material, the pools dry, the embryos pause development, and the next rains trigger a mass hatch. You can reproduce this cycle with a simple peat method and careful timing.

Spawning setup
Place one male with one to three females. Provide a container of rinsed, boiled, and cooled peat moss or coco fiber about three to five centimeters deep. Use a yogurt cup or small food storage box. Add leaf litter and clumps of moss around the container to encourage the pair. A small sponge filter provides circulation without disturbing the substrate. Keep light subdued and add floating cover.

Spawning behavior
The male courts with short displays and quick approaches. The pair noses into the peat and deposits eggs below the surface. Allow several days of spawning so you collect a good number of eggs. Feed small live foods often to maintain condition.

Collecting the medium
Lift the container, pour off water through a fine net, and gently squeeze the peat until it is evenly damp. The correct moisture feels like a wrung out brownie that clumps when pressed but releases only a drop or two when squeezed hard. Spread the peat thin and pick out debris. Candle a few eggs in a clear spoon under a bright light to confirm a good take.

Bagging and storage
Place the damp peat with eggs in a labeled zip bag or airtight container. Leave a small air pocket, seal, and store in a dark place at room temperature. Record date, parent line, and room temperature. Check weekly for excess condensation and mix gently if needed so moisture stays even.

Incubation timing and diapause
Embryos pass through paused stages called diapause. Practical timing at room temperature is often eight to twelve weeks for this species, though lines vary. Begin test wets once per month starting at week eight. If many eggs are still clear, wait another two to four weeks. Look for silver eyes and visible twitching inside the egg, both are reliable signs that hatching is near.

Test wetting
Place a small pinch of peat in shallow soft water at about 24 to 26°C with very gentle aeration. Use a depth of five to ten centimeters so fry can reach the surface easily. Many eggs hatch within one to three hours, others over the next day. After twenty four hours pour fry and water into a grow out container. Return the peat to the bag, remove excess water, and store again. A second hatch is common two to four weeks later.

Hatching cues
Fresh soft water, a small drop in conductivity compared to storage, and a slight temperature change can all help. A few drops of peat extract or rooibos tea is a traditional cue. Some breeders note higher hatch rates when a low pressure weather system passes. Keep light subdued.

Fry rearing
Do not feed immediately, most fry still absorb a small yolk for several hours. Start with infusoria, rotifers, or a quality fry powder that clouds near the surface. Add vinegar eels on day one and microworms on day two or three. Move to newly hatched brine shrimp as soon as bellies can handle it. Feed tiny portions four to six times daily, remove leftovers with a turkey baster, and perform small daily water changes with aged water of similar chemistry. Use a seasoned sponge filter with prefilter foam to prevent entrainment.

Protecting eggs and stray fry in a display
If a pair remains in a planted display, expect some eggs to be laid outside the peat cup. Rock piles, larger gravel pockets, and dense moss give those eggs and any surprise fry a better chance. For planned breeding the peat method gives higher yield and control.

Troubleshooting
If fungus appears during a test wet, add a very small amount of methylene blue to the hatching tray and improve cleanliness at the next collection. If eggs collapse in storage, the peat was too dry. Add a teaspoon of clean water, mix, and recheck in twenty four hours. If many embryos reach silver eye stage but do not hatch, try a cooler test wet at about 22°C, then a slightly warmer one, or rebag for two more weeks and try again.

Line management
Keep notes for each line that include parent identifiers, storage dates, test wet dates, hatch rates, and growth. Rotate males between females on different weeks to spread genetics. Label carefully so you can repeat the best results.

Quick Facts

• Scientific name: Hypsolebias magnificus
• Origin: Middle São Francisco River basin, Brazil
• Size: About 5 cm, which is about 2 inches
• Temperature: 22 to 26°C, which is 71 to 79°F
• pH: Commonly around 6.5 to 7.5, stability is more important than exact values
• Temperament: Generally peaceful, best as one male with one to three females
• Diet: Small live and frozen invertebrates, can be trained to accept fine prepared foods
• Breeding: Annual substrate spawner that lays in peat or similar medium with dry incubation of eggs, no parental care

Tropical Fish Co. Notes

Think of this fish as a seasonal firework that you can time yourself. Quiet water, leaf litter, small live foods, and soft light are the recipe for color that seems to glow. The peat method feels like gardening. You plant a little seed bank of eggs, tend the bag through the dry season, and on a rainy day of your choosing you wet the medium and watch tiny sparks of life appear. Careful records turn a good year into a great one, and each successful hatch keeps these beautiful lines strong for the hobby.