Killifish / Aphanius dispar – How to Hatch & Breed Arabian Killifish
Today we’re looking at Aphanius dispar, commonly known as the Arabian killifish — a hardy, adaptable species from the Middle East.
This species naturally occurs in:
- Egypt
- Israel
- Jordan
It’s one of the most adaptable killifish you can keep — but there are a few tricks to getting the eggs to hatch reliably.
Buying & Shipping Eggs
In the example shown, 20 eggs were purchased for around £19.
These arrived in a breathable bag inside a polystyrene box. A breathable bag allows:
- Gas exchange (oxygen in, CO₂ out)
- Fry survival if they hatch in transit
However, there are downsides:
- Eggs can stick in the folds of the bag
- Hard to count eggs accurately
- Water-filled bags may trigger customs issues internationally
- Eggs are more vulnerable to crushing if not boxed well
Many breeders prefer sending eggs in small rigid tubes to prevent crushing — especially for worldwide shipping.
Because Aphanius dispar hatches quickly (10–14 days), there’s always a risk that fry will hatch while in the post.
Incubation Period
This is a rapid hatching species.
- Typical hatch time: 10–15 days
- Often already “eyed up” (visible eye spots) when received
If eggs are overdue and not hatching, they may need a trigger.
Triggering Stubborn Eggs to Hatch
In this case, the eggs were fully developed but refused to hatch.
Methods tried:
- Sunlight exposure (no success)
- Adding cold water (no success)
- Cold-to-warm temperature shift (success)
What worked:
- 3 days at ~18°C
- Then moved to 25–26°C
Within hours, eggs began hatching.
For this species, a temperature swing from cool to warm appears to trigger hatching.
Hatching Setup
Use:
- Shallow plastic container
- Around 1 inch of water
- Mature tank water preferred
- Hard water
Important note:
Killifish fry hate sudden water chemistry changes. Avoid constantly moving them between containers.
Instead:
- Hatch and raise in the same container initially
- Top up water gradually over time
- Avoid large water changes
Water Parameters (Very Important)
Aphanius dispar is a hard water species.
- Tolerates 15°C to 30°C
- Prefers hard, alkaline water
- Benefits from added salt as they mature
Many breeders add:
- Small amounts of salt for conditioning
- Up to 2 teaspoons in a 9-litre tank for adults
This species tolerates:
- Freshwater
- Brackish water
- High salinity
That adaptability is part of why they’re so successful in the wild.
First Foods for Fry
Most fry are large enough to take:
- Baby brine shrimp
- Microworms
However:
- Some fry may be smaller
- Keep infusoria ready just in case
Some individuals may rely briefly on a yolk sac before feeding.
Always be prepared with multiple live food options.
Tank Size & Setup for Adults
Minimum tank for breeding trio:
- 60 cm x 30 cm tank
- Sponge filter only
- No heater required in most indoor settings
Breeding options:
- 1 male + 2 females (minimum trio)
- Small group in larger tank
Aggression Warning
Males are highly aggressive.
- Constant flashing and dominance displays
- Weaker males may be killed
- Females can be harassed heavily
If keeping multiple males:
- Provide space
- Provide line-of-sight breaks
- Expect a dominant male
Spawning Behavior
In the wild:
- Gravel spawners
In aquariums:
- Lay in gravel
- Lay in filamentous algae
- Lay in spawning mops
Best method for egg collection:
- Use dark green wool mops
- Let mop touch both surface and bottom
- Check regularly
If eggs are left in tank:
- Adults will eventually eat them
Growth & Size
- Maximum size: ~8 cm
- Slow to moderate growth
- Extremely hardy once established
Many UK breeders have successfully kept and bred this species outdoors in summer ponds.
Buying Advice
If purchasing eggs:
- Don’t rely on just 20 eggs
- Expect losses
- Buy multiple batches if possible
- Hatch in separate containers for safety
With only a single pair reaching adulthood, breeding success isn’t guaranteed — especially with aggressive males.
Final Thoughts on Aphanius dispar
This is one of the toughest and most adaptable killifish species available.
Key points:
- Rapid hatcher (10–15 days)
- Hard water specialist
- Benefits from salt
- Aggressive males
- Trigger hatch with temperature swing if needed
- Extremely tolerant species
If you want a hardy, bold killifish that tolerates a wide range of conditions — Aphanius dispar is an excellent choice.
Just be prepared for attitude.
