Coconut breeding cave

[Wilfried]

Reading about breeding caves, I have seen two versions of the aperture: some have a round hole near the center top of the shell, others have the aperture on the rim which makes contact with the substrate.
I like to try to breed A. megaptera... will the aperture make any difference? Or do they prefer different caves? Any suggestions?

 

[dw1305]

Hi all,

Reading about breeding caves, I have seen two versions of the aperture: some have a round hole near the center top of the shell, others have the aperture on the rim which makes contact with the substrate.
I like to try to breed A. megaptera... will the aperture make any difference? Or do they prefer different caves? Any suggestions?

You want a small hole in the coconut rim and at substrate level.

This allows the female to adjust the hole to the size she wants with sand. Have a look at <"ideal spawning cave">, unfortunately it has lost its images.

cheers Darrel

 

[Wilfried]

Thank you, Darrel
Will try and report how this worked out.

 

[Bart Hazes]

This is what Darrel is referring to. It's my female A. norberti who engineered the cave entrance so only she could get in. During spawning she would reside more or less permanently inside the cave with the male visiting the entrance about once a minute, tilting his belly towards the opening and using his pectoral fins to, I presume, distribute sperm into the cave. On one occasion the female stuck just her head out and seemed to be finning, perhaps to further mix the sperm around. I've always wondered if the female communicated with the male so he knew when his services were required or if the once-a-minute is good enough to ensure live sperm are floating around all the time.
With another pair the female dug a cave below a piece of driftwood and I have had Apistogramma sp. Melgar and allpahuao spawn on the underside of an oak leaf, and macmasteri and eremnopyge high up in a depression in driftwood. There may be some species-specific preferences but it is best to give them different options and don't be surprised if they pick another spot you hadn't considered.

 

[Wilfried]

Thank you, that is really informative.

 

[Wilfried]

Well, let's see how this will work out...

 

[Bart Hazes]

Rather coarse gravel, may be hard to pile up for the female. But not all of them do so it may work. If she is not interested you can also make the opening smaller but pushing that side of the coconut deeper into the gravel.

 

[Wilfried]

Well, it took less than an hour for both to enter and inspect the cave. And both do move gravel, they constantly pick some to spit it at another place.
Don't know if it is due the water change I made while placing the cave, but both look a lot more animated doing their tail flashing. My new pH meter is on the way, meanwhile I only can check TDS, which is 20 ppm at 24°C... so, let's wait and see how things keep moving.
And I need to practice my photographic skills... they move too much to get sharp photos...

 

[Bart Hazes]

Sounds promising. Time to cancel your TV subscription as you won't need it any more

20 ppm is great and your pH is likely at least 6.5 perhaps a bit lower already. I don't know what species you have but for many that is enough to get going.

 

[Wilfried]

Well, I got a pair of WC A. megaptera, if I remember well from the Atabapo region. As far as I could find out, they breed at pH of 4.5 and 5 ppm. I think I'll have to put some catappa leaves somewhere in the acuarium.

 

[Bart Hazes]

I have not seen dramatic pH reductions due to driftwood or leafs. Some things that work well in a jar with RO water, like ADA Africana substrate, don't work as well in a tank. The pH in some tanks has now dropped to the 5.5-6.0 range whereas plain RO water is 6.3-6.5. That said, your TDS is close enough to where it needs to be that I would not be surprised if they breed. If they spawn but eggs don't hatch you may still need to bring pH further down. I had that happen with an A. pantalone spawn at about pH 6.5. They are now near 5.5 and I hope they will try again.
Megaptera is a very nice fish and very much worth getting them to spawn and raise the offspring.

Best of luck!