Threadfin Rainbowfish (Adults and Fry)
September 8th, 2008In a 20L aquarium, I have a small colony of Threadfin Rainbowfish, Iriatherina werneri, that I’m attempting to breed. These blue-eyes are beautiful fish that I’m hoping to eventually have a huge school for my 75G aquarium. The males are especially brilliant, displaying long fins, which they use constantly to prove their dominance to other males, and to impress females.
The males also tend to get a striking headlamp, a bright yellow/orange stripe along the top of their head, when they’re courting females. The females are not pictures here, but they do not have the elongated fins that the males do. It’s quite easy to tell them apart due to the noticable difference in finage.
As you can see from the backgrounds in these pictures, I’ve been using spawning mops made from acrylic yarn to try and harvest eggs. The goal is to float these mops, have the fish lay eggs, and then remove the mop and place it into a hatching/rearing tank. By cycling two mops between these tank every 10-14 days, I hope to constantly have new fry. So far, I’ve been successful, but only on a very small scale.
The fry are absolutely tiny when they first hatch; no more than a millimeter or two long. Right now, I have a couple that are 5-6mm long, but recently lost some to a Hydra infestation. I feed the newly hatched fry GP 5micron powder, which besides green water is just about the only thing that will fit in their tiny mouths. I’ve started feeding the larger fry some baby brine shrimp. Hopefully, they’ll grow up fast, and will be able to go in with the adults soon. If anyone’s successfully bred and raised these fish, I’d love to hear some advise.
September 8th, 2008 at 8:09 am
These are new to me, what a striking fish. Well done in breeding them.
September 8th, 2008 at 3:22 pm
oh that acrylic yarn finally has a noble use!
great photos
September 8th, 2008 at 3:32 pm
They are beautiful and I’ve never seen or heard of them before. Do they eat their fry?
September 8th, 2008 at 4:47 pm
They’re great little fish. The fry are tiny, so the adults will eat them, although I’ve heard of some folks having success breeding them with the adults when the tank is crammed with java moss. I don’t have enough moss to fill a 20G tank though, so I’m separating them out.
October 22nd, 2008 at 7:07 pm
[...] replaced them with about 60 Threadfin Rainbowfish (Iriatherina werneri) that I had kept in quarantine for the last few weeks. I also intend to fish out [...]
December 21st, 2008 at 10:25 pm
[...] tank is also packed with about 50-70 Iriatherina werneri (Threadfin rainbowfish), and a few other Melanotaenia praecox (Dwarf Neon rainbowfish) that I had from another tank. While [...]
December 11th, 2009 at 12:12 am
I have managed to breed Threadfins in a 1 foot tank at 21.5 degrees and a pH of around 7.5-8.0. Although I was trying to breed from the pair, I was unaware that they layed eggs until I saw a few babies at the surface, and they were absolutely tiny, I struggled to see them at times.
March 2nd, 2010 at 8:57 pm
Gorgeous rainbows! Seeing the Appistos you work with and the F1 angels I’m wondering if you do anything to your water. If so what are the parameters these rainbows kept in?