Amblydoras nauticus spawned

[bekateen]

Hi All,

Back in November 2022 (this post), I imported 4

Amblydoras nauticus

from a creek off the Rio Nanay outside of Iquitos, Peru. Today I discovered four ... correction, five... fresh eggs!

Tank setup is a 20-gallon long with a thin layer of sand substrate. The tank gets a 70% water change every two weeks with a 50-50 mix of tapwater and RO water, the tapwater dechlorinated. Decorations include a few bamboo pipes, about 1" to 1.5" diameter and about 4" long, a couple of pieces of wood (branches really, not blocks of wood), a small terra cotta pot with a small Crypt plant in it, and a spawning mop hanging from a cork. There is also a small Pothos plant hanging out of the tank, with its roots in the water. The tank has a sponge filter with a modest air flow (not strong, but not trivial). I initially fed them live California blackworms, but for the last few months, those haven't been available, so I switched to frozen bloodworms two months ago. There is an LED light on a 12 hr timer.

I've made a few changes earlier this week, any one (or all) of which may have been triggers to spawning:

• The heater used to be set at 76F. Two days ago I bumped it up to 78F.
• Also two days ago, I switched the light from its "white light" setting to a "blue light" setting.
• Previously, I was feeding them every other day or daily, but three days ago I upped the feedings to 2x - 3x per day.
• Finally, (and just to be clear, I didn't make this change; it just happened ), it's been raining a lot in my region, so the weather may have been a factor.

Four eggs were in the spawning mop, and one was in the sand. They look fertile, but time will tell. I used a turkey baster to blast gently the sand surface, hoping to stir up more eggs, but I found no more.

The eggs are slightly oblong, just over 1 mm on their long axis, and have a pale amber color with a significant transparent jelly coat around them.

I hope they develop, and you know I'll be hunting for more eggs.

Cheers, Eric

P.S., There isn't much known about Amblydoras spawning, but mating has been observed a few times (although egg raising wasn't successful in any of the cases I'm aware of). Here's what I found as a forum search of past threads:

• Amblydoras spawn by @Doradid
  • This thread has a link to a YouTube video showing spawning. The link is now dead, but I think there is a similar video here: Amblydoras spawning (I'm embedding the current video under this set of bullets). Does anyone know if this new video is from the same person?
• Breeding Doradids by @Divemaster
  • No spawning was reported, but it's a great discussion of setup.
• Amblydoras nauticus species Tank by @Phyllonemus
  • This post describes suspected spawning behavior, but no spawn confirmed.
  • Phyllonemus has several Amblydoras YouTube videos too: https://www.youtube.com/@zappa0609/videos

To be clear, the video below is not mine. I think it belongs to @Doradid:

[JohannesH]

Awesome hope the eggs are fertil

[Jools]

I saw the blog report update, wow. That's a pretty cool one!

Jools

[bekateen]

Awesome hope the eggs are fertil

I saw the blog report update, wow. That's a pretty cool one!

Jools

Thanks to both of you!

I think I need to set up an egg catcher for these. They are obviously egg scatterers, and the female was really fat, so I'm sure she laid more eggs than these five. I pushed the sand from the back of the tank to the front using a turkey baster, gently blasting the sand to stir up light objects (i.e., eggs), but I saw no more eggs after doing that. I've read in other reports that they eat the eggs almost as fast as they lay them. Yikes! LOL I need to put an egg catcher in the tank.

Cheers, Eric

[sturiosoma]

Congrats Eric and of all the fish you brought back I like the Hemis and Morrowis the best and have you ever purchased fish for others, kinda of like when you go could you see if they have this or would that be too much of a headache.

Jeanne

[bekateen]

Congrats Eric and of all the fish you brought back I like the Hemis and Morrowis the best and have you ever purchased fish for others, kinda of like when you go could you see if they have this or would that be too much of a headache.

Jeanne

Hi Jeanne,

Yes I did that last time. Honestly, the shipment this year didn't go well. Most of the fish arrived alive, but I lost many fish in the first 2 weeks home during QT. I was planning to split the

Hemiodontichthys

and the

Panaqolus albomaculatus

in half with two friends. Of both groups, only 3-5 fish survived out of about 20. I also lost all the

Callichthys

, although the

Dianema

and

Megalechis

are doing okay.

I may do it again in the future, but probably not on this scale. It's much safer to let someplace like WetSpot or other importers QT the fish and get them healthy then buy retail. The price per fish is much higher, but the survival rate is too.

Cheers, Eric

[bekateen]

Found a sixth egg today. It seems to have been laid yesterday, as it has an obvious embryo on it, although I don't know if it's alive. It lacks its jelly coat.

The other eggs are still going, and I can see tiny embryos growing on them too.

Cheers, Eric

[Shane]

This is fantastic! Glad you noted the lighting change as I think photoperiod and light intensity are potential triggers. In the rainy season the environment goes from clear bright skies and the pounding heat of tropical sun to cloudy and dark. I am confident that this is one of the triggers that tells fish "time to spawn.'

-Shane

[Jools]

the environment goes from clear bright skies and the pounding heat of tropical sun to cloudy and dark.

It's the reverse in Scotland. [Brought to you by the Scottish weather channel, https://taps-aff.co.uk/]

Back on topic, the humidity and other factors change too. Makes a lot of sense...

Jools

[bekateen]

Thanks Jools and Shane!

Three

Amblydoras nauticus

have hatched this morning and I see one additional egg unhatched. Don't know what happened to the other two.

The hatchlings are tiny! They remind me of cory hatchlings.

Cheers, Eric

[characinkid]

Thank you!

This is very cool, great to see new sp. being spawned like this so we can learn about them.

[bekateen]

Adding a sloppy false floor on the front 1/3 of the tank under the spawning mop and potted plant: Two layers of ceiling light egg crate, one placed atop the other, and the bottom layer has a fine mesh net tied to it.

Let's see if this improves egg recovery on the next spawn.

Cheers, Eric

[naturalart]

Congrats on the import and spawn. Cool fish.

[bekateen]

Thanks, Clay!

Here's a photo of the only fish in the tank I know for sure is female (the photo in the OP is of the largest fish, I suspect a male):

Cheers, Eric

[knifegill]

Aye. You have succeeded where I failed. Well done!

[bekateen]

Thanks!... but not that you failed I mean.

[bekateen]

A rare sighting of three of the four adults at the front of the tank (female on lower left). They think they're hiding.

Cheers, Eric

[bekateen]

Amblydoras nauticus

photo update, 1 day old. The bits stuck to it are from mulm I added to the breeder box to provide infusoria for when these start eating

[Bas Pels]

You mustbe a very happy man

All the luch with raising the fry

[sturiosoma]

Adding a sloppy false floor on the front 1/3 of the tank under the spawning mop and potted plant: Two layers of ceiling light egg crate, one placed atop the other, and the bottom layer has a fine mesh net tied to it.

Let's see if this improves egg recovery on the next spawn.

Cheers, Eric

Hey Eric are your fish big enough to where they won't fit thru the holes in the egg crate.

Jeanne

[bekateen]

You mustbe a very happy man

All the luch with raising the fry

So far, yes I am! (Unless a tragedy strikes )

Hey Eric are your fish big enough to where they won't fit thru the holes in the egg crate.

Jeanne

The fish have wide heads so I think they can't fit through the egg crate. In the future, I'll take more time and make a better cover with a finer cover.

Cheers, Eric

[bekateen]

Just got home after 2.5 days out of town. I saw two live babies, dont know if there's more. It's late now. I'll check tomorrow and get new pics.

Cheers, Eric

[bekateen]

Amblydoras nauticus

photo update, 4 days old, 6mm SL

[bekateen]

Amblydoras nauticus

photo update, 5 days old. These photos are frame grabs from a video taken through a dissecting microscope.

Cheers, Eric

[bekateen]

Easter egg hunt came early! New eggs this morning (SPAWN #2). I found and collected 6 eggs (they all look to be fertilized) from the spawning mop, and I still see at least one egg in the tank. Haven't yet had time to collect the loose eggs in the tank. Next step is to flush the false floor, to see if that resulted in more eggs being collected. Just need to do it before lights off tonight, because that's when the parents will come out again and might hunt the remaining eggs. Fingers crossed!

Update: I took about 20 minutes using a turkey baster to blast then suction the sand and debris trapped by the plastic egg crate. I've only gotten through about 1/5th of the individual squares (yes, I'm going square by square) and I've harvested an additional 30-35 eggs. Most of the eggs look good and fertile (transparent jelly coats with amber-yolked eggs in the center) but five of the eggs have been overenlarged jelly coats with opaque white objects in the center. After I finish working in about two hours, I'll go through the rest of the egg crate. If egg capture continues near this rate, I should be around 80-100 eggs by the time I finish!

Cheers, Eric

[characinkid]

Thats very cool Eric, congrats. Im interested in if the eggs are falling all the way through the fine netting or are trapped above the netting in the egg crate?
I've been looking for a good way to catch tetra/characin eggs and been thinking of a similar method as you have here but with the egg crate slightly offset so as to prevent congo tetras for example getting to their eggs. Ive also tried to put a layer of plastic netting over the egg crate to let the eggs fall through that.

[bekateen]

I just finished going through the egg crate using the turkey baster. I found only about 10-20 more eggs. My conclusion is that the fish spawned primarily underneath the spawning mop (nearly all of the eggs were recovered in the first 5-6 rows of the egg crate, directly underneath the spawning mop - very few of the eggs were found in the parts of the egg crate that were NOT covered by spawning mop).

Also, a significant number (about 10%-20%) of eggs I found (in all places) were the larger, milkier eggs.

Milky eggs obvious

Clear eggs marked with arrows

Now I'm wondering if they're really "bad eggs" or if they might have been laid a day ago. I say that because these are so much larger than the "good eggs" with yellow yolk that maybe they've had more time to absorb water and swell... Either way, time will tell.

Thats very cool Eric, congrats. Im interested in if the eggs are falling all the way through the fine netting or are trapped above the netting in the egg crate?
I've been looking for a good way to catch tetra/characin eggs and been thinking of a similar method as you have here but with the egg crate slightly offset so as to prevent congo tetras for example getting to their eggs. Ive also tried to put a layer of plastic netting over the egg crate to let the eggs fall through that.

So the way I set up the egg crate and fine plastic screen is this way:

• Bottom layer is fine plastic screen. This screen is too fine to let the eggs fall through.
• Next is a layer of egg crate.
• On top of that is another layer of egg crate, but with the top layer positioned askew (offset, like you mention) of the lower layer, as seen HERE. In other words, if the fish is looking straight into one square of the top layer, it's looking at the corner between four squares in the lower layer. Thus, the fish is blocked from reaching to the bottom layer to get eggs that sink down to the fine plastic screen.

To retrieve the eggs, I remove the top layer of egg crate and blast the lower layer with the turkey baster. The eggs drift up into the water column, at which time I suck them up while they're "drifting" in the water, before they can settle back into the crate.

Theoretically, I should be able to lift the lower egg crate out of the water and the eggs should be caught by the fine mesh underneath, but I haven't tried that yet.

I'll post video when I'm able.

Cheers, Eric

[bekateen]

From first spawn,

Amblydoras nauticus

photo update, 7 days old, 6.3 mm SL.

[bekateen]

Here's what it's like to hunt for eggs. I spent about 45 minutes doing this and collected a total of about 50 eggs. Not counting the eggs in the spawning mop, nearly all the eggs were collected from the first 5 or 6 rows of the plastic, which corresponded to the position of the spawning mop.

Cheers,
Eric

YouTube URL: Amblydoras nauticus spawn: Hunting for eggs

[aquaholic]

Well done!

I've noticed I get a better egg hatch rate when eggs are prevented from touching each other.
I use the fine mesh under egg crate concept with one individual egg in each compartment, stacked several layers high with gentle down flow. Boost the dissolved oxygen with an airstone in a corner, raise temperate for faster hatch and can use UV if fungus becomes a concern. For the screen, I use a fiberglass midge mesh product. Superglue to fasten.

Alternatively another setup suggestion:
I use open top plastic drinking cups with an electronic soldier iron to create small holes around the sides, 3 cm off the bottom so you can pick up a cup without it completely draining out. These are useful for individual hatching and then raising fish that would normally eat each other. It's easy to feed through the open top and you can buy a thousand cups relatively cheaply that neatly stack when not used. The plastic tote trays can stack vertically as well.