The third bag of eggs I received was Hypsolebias sertanejo – another annual killifish, and like most annuals, patience is key.
This species has an incubation period of 2 to 6 months. The eggs I received had already been in peat for around two months, so they were potentially close — but not guaranteed.
First Inspection – Not Ready Yet
I had a quick look through the bag and couldn’t see any eyed-up eggs. Still, I emptied a portion out just to double-check properly.
After checking about a third of the peat, I counted at least ten eggs… but none of them had eyed up yet.
So, back into the bag they went.
That’s one of the big differences with annual killifish compared to mop-spawning or semi-annual species. You’re not just collecting and hatching — you’re managing incubation timing, temperature, and development over months.
Depending on temperature, these can take the full six months before they’re ready.
A Few Weeks Later – They’ve Eyed Up
After storing them for several more weeks, I checked again — and this time I could clearly see that most of the eggs had eyed up.
These eggs were originally collected on 26th March, and I was checking them again on 7th June — so roughly two and a half months.
Because I’d been keeping them in a heated cupboard, the warmer temperature seems to have pushed them toward the shorter end of the 2–6 month incubation range.
Temperature makes a huge difference with annuals.
The Wetting
Once I confirmed the eggs were ready, I poured the peat into a bowl of water.
From experience, once eyed up, they usually begin hatching within a few hours. I expected activity within three hours — and I wasn’t wrong.
Day 1 – A Strong Start
On the first day, I could already see fry swimming.
I carefully removed them using a turkey baster and transferred them into a separate container.
Very important:
The water you move them into must match the exact water chemistry they hatched in. Even slight differences can send these tiny fry into shock.
These fry are absolutely minute.
By the end of day one, I had collected 13 fry.
Because of their size, you must have live micro-food ready:
- Infusoria
- Paramecium
After the first few days, once they’re strong enough, you can transition them onto baby brine shrimp.
I knew there were over 40 eggs in the bag, so I left the hatching container for another day to see if more would emerge.
Day 2 – Slowing Down
Day two produced just two more fry, bringing the total to 15.
They’re surprisingly tricky to catch at this stage — tiny and fast.
The 13 from day one were feeding well, which is always a good sign. If they’re actively feeding, your survival rate improves dramatically.
I left the bowl again for another 24 hours.
Day 3 – The Last One
On day three, I spotted just one final fry.
That brought the total to 16 fry from around 40 eggs.
At that point, I drained the peat through a net, gently dried it, and re-bagged it. I’ll store it again for another week or two and attempt a second wetting — sometimes you’ll get a staggered hatch with annuals.
Final Thoughts on Hypsolebias sertanejo
Out of roughly 40 eggs, I ended up with 16 fry on the first wetting.
Not bad — but not a full hatch either.
With annual killifish like Hypsolebias sertanejo, success comes down to:
- Correct incubation temperature
- Confirming eggs have clearly eyed up
- Matching water chemistry exactly during transfer
- Having live micro-food cultures ready before wetting
- Being prepared to re-dry and try again
They’re not difficult once you understand the rhythm — but they demand patience and preparation.
And when you get it right, watching that first fry dart around the bowl makes it all worthwhile.
