Breeding Nannostomus Marginatus

[Daneland]

Initially I bought them for my Apisto tank but after Apistos died, I moved them a smaller 30 litre tank. At one point I decided to change the substrate with an active substrate (acadama) to keep pH low.Than I lost two of them. The other 3 look settled for now. As I want them to breed, I gradually reduced pH and TDS with RO water and alder cones/dried leaves. Water is now very soft TDS meter shows 30-40 pH is around 6. I feed them nearly everyday with Grindal worms (thanks @dw1305 )I started to do water change with RO ( or cooling the tank water and adding back, thanks @Edvet for the idea)But they dont spawn.
There is a spawning mob (acrylic yarn) and a few Buceps, anubias, crypt and plenty of floating plants in the tank but not heavily planted at all. One of them is a female, it has a quite a big belly and broader body, the other is a male slimmer and the third one is likely a female ( has a broader body but not a big belly yet). Male relentlessly chases the other two but no action happens, females keep running and hiding. They look pale too. They eat nicely the worms but I realised that they cant eat much so I feed them 3-4 times a day with smaller portions.
What else I can do to condition them?Or am I doing something wrong.
Thanks in advance

 

[alto]

I assume you’ve read breeding reports ...

Male relentlessly chases the other two but no action happens, females keep running and hiding. They look pale too.

I suspect that is your answer - these fish sound stressed (pale) & with the male chasing that much, females won’t be inclined to spawn
I suggest moving them back to the bigger tank & see if they begin to relax & display color
Then move a “ready” pair over to the spawning tank when they are showing signs of “interest” and breeeding colours

You may need to increase group size to 10 or more for them to become interested in breeeding (& reduce stress), most fish species seem to prefer multiple males & females available for “choice”

 

[mort]

I agree that more would be beneficial. I have nannostomus beckfordi and the males spend a good proportion of the day displaying and socially bickering amongst themselves, leaving the females in peace. I also have the tank really heavily planted and notice a few babies every now and then (never more than 1 or 2) amongst the vegatation. They spawn after a water change and the water is normally slightly warmer (I'm thinking it's the influx of new water rather than the temperature that's important).

I don't feed Grindal worms but do use newly hatched baby brine, daphnia and cyclops, plus a staple dry food mixed with a little Spirulina. There is also a large population of cherry shrimp in the tank so they might be finding their own live food. I would say variety is the key.

My water is just below neutral and tds 100-150 but I don't think water is your issue and would agree with everything alto has said above. Give them some time, a little space and up the numbers if possible.

 

[Daneland]

I added another 5 now there are 8 of them in a large tank with more plants and few red neocardinias. Chasing has finished, some small poking still happen. I hope I will see some fry soon.

 

[Daneland]

I think my breeding project has not been completely unsuccessful.Today I noticed a decent size fry in the small tank. They must have spawned at some point and one of the eggs managed to survive. This is encouraging! I will try to breed in small tank with a better setup. But the fry looks interesting it is quite dark almost brown.I hope it survives. I love this hobby

 

[dw1305]

Hi all,
That is definitely a pencil fish fry. I've not seen Nannostomus marginatus fry, but it looks like N. beckfordii fry do.

cheers Darrel