Buytaert's killifish

Where they come from

Buytaert's killifish is a forest stream specialist from Central Africa, found in shaded creeks and seepages in the Gabon/Congo region. Think leaf-litter beds, tea-colored water, almost no current, and cool nights. That soft, acidic blackwater is the vibe you want to channel.

Setting up their tank

They do best in a species-only setup. A trio (1 male, 2 females) in 8-15 gallons works well. Go for a dark substrate, piles of leaf litter, and floating plants to knock down the light. Use a gentle sponge filter and keep the flow minimal.

• Temperature: 68-73 F (20-23 C) - cooler nights are fine
• pH: 5.5-6.5
• GH/KH: very low (GH 0-3, KH 0-2)
• Conductivity/TDS: 50-120 uS (25-80 ppm) - RO or rainwater mixed with a little tap works well
• Light: subdued, with floaters like Salvinia or frogbit
• Aquascape: dense cover, fine plants (Java moss, Najas), yarn mops, leaf litter, alder cones

What to feed them

They have small mouths and perk up for moving food. Mine put on weight and color fast with a live-and-frozen routine. Some will take high-quality micro pellets, but do not count on it at first.

• Live: baby brine shrimp, Daphnia, mosquito larvae, grindal/white worms, wingless fruit flies
• Frozen: baby brine, cyclops, daphnia, chopped bloodworms (sparingly)
• Dry (if they accept it): small soft micro pellets, crushed high-protein flakes

How they behave and who they get along with

Males display a lot and can be pushy, so give them line-of-sight breaks. In a roomy, planted setup a single male with two or three females is smooth sailing. They are shy around boisterous fish and will hang near the top or in cover.

• Best: species-only tank
• If you must add company: tiny, calm fish that like soft water (e.g., small pencilfish) and will not outcompete them for food
• Avoid: fast tetras/barbs, nippy fish, larger killies, anything that likes hard/alkaline water
• Shrimp: adults may be fine, but shrimplets are snacks; snails are fine

Breeding tips

They are mop spawners and will lay daily in good condition. Parents will eat eggs and sometimes fry, so either pull the eggs or move adults out.

• Set up a trio with 1-2 floating yarn mops and one bottom mop.
• Collect eggs daily. They are adhesive and usually found in the upper mop.
• Incubate in water with a drop of methylene blue or over damp peat at 70-72 F (21-22 C).
• Hatch time: typically 10-21 days. Wait for eyes to darken before wetting peat or moving eggs to hatch water.
• Fry first foods: infusoria for a day or two if needed, then microworms/vinegar eels, then baby brine.
• Keep fry shallow (4-6 inches of water) with gentle air and daily small water changes using the same soft water.

Common problems to watch for

• Jumping: lower the waterline a couple inches and seal every gap in the lid.
• Overheating: anything above 75 F (24 C) long-term shortens their lifespan and invites disease.
• Velvet (oodinium): shows up in stressed, warm, brightly lit tanks. Dim the lights, cool the tank, and treat early.
• Hard water breeding issues: poor hatch rates and lots of fungused eggs in mineral-rich water. Switch to softer water for eggs and fry.
• Male harassment: add more cover or switch to a bigger footprint and adjust the ratio to 1M:2-3F.
• Fin nips and dull color: usually too much flow or bright light. Add floaters and reduce current.
• Shipping/acclimation stress: keep them quiet and dark for the first day, feed lightly, and skip big water changes that week.