- I recently did a video about advancements
in captive breeding of Acropora millepora
by using tiny little baby tuxedo urchins
to munch away the algae
that surrounds the newly-settled coral.
And there was a lot of excitement
and comments on that video.
And just in general,
trying to breed corals ourselves in the hobby
seemed like something people were interested in,
so I wanted to do a follow-up video specifically about that.
We're pretty good about growing coral
from even the tiniest little frag that breaks off,
so I think we can really take the hobby to the next level
and get captive breeding of these corals going as well.
So, what should you know
if you're considering breeding acropora in your own tank?
Hi, guys and girls, I'm Reefman,
and this week's all gonna be about what you need to know
to breed your own Acropora corals at home.
So, first off, I think it would be useful to know
the lifecycle of an acropora coral.
No, they don't start out as tiny frags on the reef.
Although storms do frag corals
just like they do in the hobby,
that's not the primary way that they reproduce.
Acropora start out as little tiny bags of eggs and sperm.
And these packets are released en masse
on one night each year.
The whole reef uses seasonal queues to spawn all at once.
And they spawn on a full moon, but the specific full moon
is actually dependent on the reef that the coral is from.
And, yes, they do remember that,
even if you've taken them from the wild
and you're growing them in captivity.
So, these packets of eggs and sperm, they're buoyant.
And if you have your pumps off,
they'll just float up to the surface
and then you can collect them off the surface of the water.
You can collect 'em in rings or however you wanna do it.
Once you've collected them, it's time to mix 'em all up.
And now, a lab would use a centrifuge for this,
so if you have a centrifuge,
then by all means spin them around 10 RPM,
but you could also just mix them.
The key is motion,
and that motion will break those bundles up
and mix all of their contents,
and, bingo, you've fertilized the eggs.
So, next up, the eggs will divide and divide again
and divide again over the next few days;
normal miracle of life stuff going on.
So, around 75 hours after fertilization,
you'll have free-swimming larvae.
And at that point, it's time to think about
the next big event that you're gonna have to deal with:
settlement.
Settlement is when the larvae will fall out of the water
on a choice bit of real estate.
And in your tank, you should have hundreds of frag plugs
which you've been growing stuff on
like bacteria and coraline
in your main reef tank for a few months,
so they're not brand new frag plugs.
Most of these frag plugs will receive more than one larva,
which will quickly grow into a single,
one tiny little polyp.
And this is where the sea urchin babies
could really help you.
Since there are literally thousands
of these little single polyps of acropora,
they're so fragile and you can damage 'em
and algae can just out-compete 'em.
Even the best teams have only been able to rear
around 50% of them,
and that's using the baby tuxedo urchins.
Without the urchins,
you might get a 10% to 20% survival rate
from your newly-settled acropora.
And keep in mind,
that's still hundreds if not thousands of baby corals,
so it's not too bad for your first go.
I've talked about zooxanthellae before,
and your new corals actually do need to get it to survive;
they're not born with it.
To do so, just move a few pieces of your parent colonies
into the tank you're using for settlement.
And Zooxanthellae can be shared in the water between corals,
so having an adult specimen of the coral in the tank
will seed your newborn corals
and help them get what they need.
Of course, corals also need food,
and these little baby corals are no exception.
Labs would use enriched live rotifers and acro power,
and maybe you wanna feed them three or more times a week.
Remember to turn off all your pumps, certainly your skimmer,
and give 'em a couple hours
before you turn on all that filtration again.
And you wanna make sure that you do feed these little corals
'cause they're so small;
they won't survive without food long.
So, how can we get our corals to actually release these eggs
and these packets of gametes in the first place?
It's all about controlling the seasons.
It helps if you know what reef your coral is actually from,
but no matter what, you're gonna need to program your tank
with seasonal temperatures
using data from a wild reef somewhere.
You need to use daylight durations and intensity
because that helps trigger acropora to mature their eggs.
And, most importantly, you're going to need
a properly-tuned simulation of the moon
free from interference from your home's lights.
I have windows here that would ruin everything.
You'll have to be a little bit crafty here
because commercial moonlights,
they just won't work right outta the box.
They're the wrong color.
For example, have you ever seen an actinic blue moon?
I haven't.
They need to be around 4,100 kelvin or so,
and that matches nature.
And of course, they're also the wrong intensity,
but you can fix that just by glueing some diffusing material
or maybe adding a resistor in line in the cable.
Something like that can get the intensity correct for you.
And I'll actually make a video
specifically about moonlights soon,
and I'll go over all the tweaks you'll need to do
to get your moonlights to be real moonlights.
So, that's it for the intro, folks.
It's really that easy.
Control the daylight, control the moonlight,
control the seasonal temperatures, control everything,
and black out your tank,
have some shades that you can draw
or a room that you can actually just make dark,
because corals growing near light pollution in the wild,
they don't spawn, at least not reliably,
and they won't spawn in your tank either
with that light pollution.
And of course, with all of this,
you still need to actually be successful
in growing acropora corals,
which is maybe not so easy for some of you.
And I'd recommend starting with just a single species
that you really wanna concentrate on for this project,
and then just grow that species
in the tank that you're working on for this.
So, I will keep an eye out for papers on the subject
of captive breeding of acropora corals,
and I'll be sure to share anything that I find
with all of you if I can find anything new.
I'll make breeding acropora
a recurring subject on the channel; I'll start a playlist.
And it's something that I really think
if we can get going in the hobby,
it'll make such a difference for us all,
and it doesn't seem to be so hard
that it's out of reach for most of us.
Like most things, it'll take devotion,
and the first people to have success,
I'm sure that they'll find ways
to make it easier for the rest of us.
Maybe not everything is quite as required as we think.
So, there are a couple papers linked down below
which I would really encourage you to read through
if you want a much more complete introduction to this topic
and you're gonna try it yourself.
But in the meantime, thanks for watching,
and let's get this going!
Bye!