Alternatives to Coco coir for dirt spawning killis

[Schuyler]

In nature, annual Killifish last their eggs in dirt so that when the pool dries up the eggs will be protected until there is water again.

In the hobby most people recreate that by giving them a jar full of coconut fiber or peat moss. The thing is that when you pull the jar out it's almost impossible to know how many eggs are in there and digging through the dirt to find the eggs is tedious.

Looking for alternatives, I found a few people on Facebook that swore their killis would use a spawning mop in a jar. My pair were just frustrated and offended when I tried that.

But looking more I found that in a lab setting they use a very fine sand (carab sea moonlight) for dirt and then they use a mesh colander and gently sift the eggs out of the sand so that they can count them and pack them in coconut fiber to incubate.

They say that this can damage some eggs. But it has me an idea: use large grain aqua soil as dirt then use a sieve with holes big enough for the eggs to fall through.

Luckily my dad lives close by and will take any excuse to justify owning a 3D printer so he made me two sizes of sieve. Then I plan to use some extra UN Controsoil and a thoroughly washed and rinsed salsa jar.

[Fish Folk]

On 2/8/2023 at 11:31 PM, Schuyler said:

In nature, annual Killifish last their eggs in dirt so that when the pool dries up the eggs will be protected until there is water again.

In the hobby most people recreate that by giving them a jar full of coconut fiber or peat moss. The thing is that when you pull the jar out it's almost impossible to know how many eggs are in there and digging through the dirt to find the eggs is tedious.

Looking for alternatives, I found a few people on Facebook that swore their killis would use a spawning mop in a jar. My pair were just frustrated and offended when I tried that.

But looking more I found that in a lab setting they use a very fine sand (carab sea moonlight) for dirt and then they use a mesh colander and gently sift the eggs out of the sand so that they can count them and pack them in coconut fiber to incubate.

They say that this can damage some eggs. But it has me an idea: use large grain aqua soil as dirt then use a sieve with holes big enough for the eggs to fall through.

Luckily my dad lives close by and will take any excuse to justify owning a 3D printer so he made me two sizes of sieve. Then I plan to use some extra UN Controsoil and a thoroughly washed and rinsed salsa jar.

Love the 3D printer applications! Good ideas here. Try it all!

I like using peat moss. I’ve used Coconut fiber successfully too, but there are properties in the peat that I especially appreciate:

(1) It is a subtle anti-fungal

(2) It lowers pH, helping to convert ammonia to ammonium

(3) For hatching, I just dump into a hatching tray — no messes.

It is true that eggs are hard to count in peat moss. But alternatively, one never knows if all visible eggs will hatch unless they’re eyed-up.

I have some hatches to wet this week. I’m not holding my breath for a huge yield. It’s just a fun process!

[Schuyler]

On 2/9/2023 at 2:01 AM, Fish Folk said:

Love the 3D printer applications! Good ideas here. Try it all!

I like using peat moss. I’ve used Coconut fiber successfully too, but there are properties in the peat that I especially appreciate:

(1) It is a subtle anti-fungal

(2) It lowers pH, helping to convert ammonia to ammonium

(3) For hatching, I just dump into a hatching tray — no messes.

It is true that eggs are hard to count in peat moss. But alternatively, one never knows if all visible eggs will hatch unless they’re eyed-up.

I have some hatches to wet this week. I’m not holding my breath for a huge yield. It’s just a fun process!

Odds are I'll just stick with the normal process but I have more eggs stored up than I'll be able to use so I figured I'll try some stuff.

I like the idea of knowing how many went in vs how many hatched. Plus doing it this way you know where the eggs are when you pack them so you don't have to dig around as much (if you use something like a petri dish). And this way you can boil the coco coir before packing it so it has less stuff to potentially fungus the eggs (in the lab they add some methylene blue too).

[Fish Folk]

On 2/9/2023 at 11:27 AM, Schuyler said:

some

SOME! methylene blue. Emphasis added. Careful . . .

[Schuyler]

On 2/9/2023 at 8:30 AM, Fish Folk said:

SOME! methylene blue. Emphasis added. Careful . . .

Yeah... I'm going to hold off on the methylene blue until I don't have small kids who could potentially get into it

[Fish Folk]

On 2/9/2023 at 11:41 AM, Schuyler said:

Yeah... I'm going to hold off on the methylene blue until I don't have small kids who could potentially get into it

Annuals live for just a season. M-Blue is forever. 💙☠️

[Schuyler]

Well that wasn't a total failure...

There was spawning behavior

It was just one day so you can't really expect many eggs. I pulled the jar, added some dechlorinated water to the container I use for growing fry, poured the soil in the sieve, and swished it around gently.

The problem is that even though I tried to sit there smaller pieces before adding them to the jar there were still more that either fit through or were the perfect size to clog the holes.

So it got clogged up and I still had to search through the dust and smaller bits. But there was one:

A wire mesh would work better for straining. I ended up putting the soil on a reptile lid and pouring water over. That seemed to work well and would have been better if it were small enough to swish on the water.

Next attempted will be to retry this but using a wire mesh. Then I'll try the fine sand method labs use.