What are these Nannostomus beckfordi doing?

[rebe]

So at first glance these I would assume this is some sort of breeding behaviour but I'm almost certain that it's two male fish. Maybe they're fighting for dominance? They've been at it for about 10 minutes now nearly non-stop, so I'm worried it's going to exhaust or stress them out too much.

I'm really hoping anybody with more pencilfish experience can help.
I'm sorry to single you out @Byron but a long time ago you were recommending pencil fish to me and you seemed very knowledgeable. Perhaps you might have some insight?

 

[AdoraBelle Dearheart]

@Byron is brilliant and I miss him being around, but he has been ill, and not online here since Jan so might not be able to respond for a while, and I don't know pencilfish I'm afraid, but tagging some people who are active and I know have kept them or know more about these species and might be able to offer some insight.

@Wills @WhistlingBadger @Slaphppy7 @Magnum Man

In the meantime, it may be helpful to know more about the tank size, number of this species you have, a pic of the whole tank, and other tankmates. Plus any recent changes to the tank, how long you've had these pencilfish, and test results for ammonia/nitrites/nitrates, just in case.

 

[Colin_T]

2 males displaying to each other or a pr breeding

 

[DoubleDutch]

Mating

 

[Magnum Man]

are they still dancing??? I had a pair of Denison's that were dancing for a couple hours before...

 

[AdoraBelle Dearheart]

Mating

@rebe just want to quickly vouch for @DoubleDutch 's skill and experience, I trust their advice, they know a lot and I would have tagged you @DoubleDutch if I'd seen you were here!

 

[DoubleDutch]

These interesting fish breed quite easy. Only think they'll eat their own eggs. The show off of males looks a bit different

 

[rebe]

@Byron is brilliant and I miss him being around, but he has been ill, and not online here since Jan so might not be able to respond for a while

I thought that I hadn't seen his posts/replies in a while, I didn't realise he was ill. I'm a relatively new member and not extremely sociable, so I missed that

In the meantime, it may be helpful to know more about the tank size, number of this species you have, a pic of the whole tank, and other tankmates. Plus any recent changes to the tank, how long you've had these pencilfish, and test results for ammonia/nitrites/nitrates, just in case.

QT, tank: 105L/29g, 75x35x40cm
Inhabitants: 12 Beckfordi pencilfish, 11 black kuhlii loaches and 1 tiny golden ancistrus
Plants: egeria densa and limnophila sessiliflora (lots of plants but recently trimmed so shorter than usual)
Water: 7.5 pH, 0 ammonia, 0 nitrites, 7ppm nitrates (tap water level)

Today I noticed the fish possibly spawning, and so I moved the three plump (eggs?) females and two males to a smaller tank, but saw them only swimming in that small tank, and then the behaviour in the video, in the original tank with the rest of the group, so I called off the plan of separating them and returned the fish to the 105L.
I've seen both the behaviour in the video and what I thought/think is the other spawning behaviour since, and the fish all seem happy.

I've had the pencils and loaches for about a week now, since 16/02/24

 

[GaryE]

I couldn't get a clear look to sex them, but if they weren't in a community, I'd expect cute little pencils. I've had beckford's (the easiest) grow up with their parents. In a community, alas, it's an egg dinner for their tankmates.

 

[rebe]

In a community, alas, it's an egg dinner for their tankmates.

Shame, I'd adore having tiny pencilfish to watch and look after!

Do they egg scatter in a way that all of the eggs will fall to the bottom? Since it's only kuhliis, maybe they'd have a chance if they didn't.

Possibly I could move either species, I do have a little 18 litre tank but that might be far too small, I haven't looked into it

 

[Mr Limpet]

N. beckfordi males spar constantly; that’s basically what they do. They’re the ones with blue tips on their ventral fins, even when not fully colored up.

If the tank is densely planted, especially with Java moss, some fry will occasionally grow up alongside the adults.

 

[AdoraBelle Dearheart]

Shame, I'd adore having tiny pencilfish to watch and look after!

Do they egg scatter in a way that all of the eggs will fall to the bottom? Since it's only kuhliis, maybe they'd have a chance if they didn't.

Possibly I could move either species, I do have a little 18 litre tank but that might be far too small, I haven't looked into it

If you're just using it as a spawning tank - like putting the three chunky (possible carrying eggs) in there with a spawning mop - then introduce the males, once they spawn, remove parents back to main tank?

Hobbyist friend I know uses a ten gallon just for spawning her cories and egg scatterers, then they return to the main tank and the smaller one is fine for raising the fry, I'm sure I've seen and heard about people doing tricks like that just to collect the eggs from their community fish. Doesn't matter that it's smaller if it's just to spawn them, that's only a few days typically I think, so it's okay when they're not living in it long term. Obviously you'd want to use tank water from the main tank in the spawning tank so when you transfer them, it's the same parameters and same temp as their usual tank.

I'm sure it was @GaryE who taught me how to make a spawning mop, it's easy! I dunno if an 18L tank is big enough or the best method for pencilfish, but worth looking into and seeing if you can get some bred! Breeding fish is pretty stressful at times, but fun and fascinating too.

 

[GaryE]

I've never successfully bred beckfordi with mops. I put them into a 10 gallon with lots of guppy grass and java moss, and the eggs they sprayed around probably landed in the moss. I didn't ever see the eggs, just young starting about a week later.

I tried mops, but that one time didn't work. It was only one try though.
They will eat their own eggs and fry, though not energetically. Tanks are small places, and what they run across, they eat. It's probably not an issue in a flowing stream.

I had fry just appear in a tank with the parents, and I also bred them by separating the sexes, taking the most 'egged up' female and a healthy male, and putting then into a breeding tank. If you have a 3rd, 4th, 5th etc wheel in there, they'll often follow the spawning pair and eat the eggs. After maybe 3 days, or if you see the female has lost girth, you remove the adults and start feeding with fine powdered food in tiny quantities.

 

[rebe]

Brilliant, thanks for the knowledge @AdoraBelle Dearheart @GaryE @Mr Limpet

I might try spawning them in the small tank if I can get my hands on a good amount of java moss or fine leaved plant! The fry could grow in the 18L until they're big enough to go back in with the parents.

Does anybody have any idea as to the "breeding cycle" of pencilfish? Say if one female spawned around now, and layed all of her eggs, how long it would roughly be until she was ready to spawn again?

 

[AdoraBelle Dearheart]

Does anybody have any idea as to the "breeding cycle" of pencilfish? Say if one female spawned around now, and layed all of her eggs, how long it would roughly be until she was ready to spawn again?

I don't I'm afraid, but conditioning the fish by keeping them in the conditions they prefer and feeding them up with a variety of food can get them into breeding condition again, although I don't know how long it would take. Since you've only had them for a week and they're already showing spawning behaviour and sparring, seems they like the conditions you have!

Seriously Fish is a really reliable website for accurate info on various species, here's the link for yours

Nannostomus beckfordi – Golden Pencilfish (Nannostomus anomalus; Nannostomus aripirangensis) — Seriously Fish

www.seriouslyfish.com

Worth reading the whole thing, but also if you scan down towards the bottom, there's a section on reproduction that looks useful.