Cynodonichthys tenuis

[stormhawk]

Just in time for CNY, the eggs I received from Shi Xuan last weekend have mostly hatched. I now have 7 fry from the set of eggs. Here's some pics:



Size comparison to live Daphnia/Moina aka "boon" that they are feeding on at the moment. You can see the facial pattern which as usual, will change with their growth rate.



Pic showing the finnage as a fry, which changes as they grow a little bigger.

Thanks again to Shi Xuan, for letting me have some eggs. I had this species some years ago but lost them to an unfortunate accident. Hopefully these 7 fry will give me better results.

[Shi Xuan]

Jianyang, you're being too courteous with me.

Hopefully, they would turn out in proportionate sex ratios. In my case, it turns out to be more females than males. They are also very shy fish, especially the male and they would dash around wildly when startled.

With the current space at a premium, I don't think I would continue with this fish anymore and would prefer to dedicate the tanks for the duboisi instead.

Let me know if you want anymore eggs. I still have some that I've collected previously in an old container with some ramshorn snails. Earlier today, I just observed a fry wriggle in an egg, so I think the eggs are about to hatch soon.

[stormhawk]

I'll let you know after CNY is over. The 7 remaining fry are growing pretty fast.

[stormhawk]

The fry have grown a little bit since the last post a week ago:



The largest one is beginning to show the typical Rivulus finnage. I hope the LFSes reopen soon. I need to get some frozen or FD Cyclop-eeze and some fresh Daphnia/Moina.

[piperon]

Hi there,

First of all, still wishes all a Happy and Joyful Chinese New Year.
Wow, those are pretty babes, I think they will glow very pretty soon.

Any eggs left to be given freely? Bro Shi Xuan.
And is it difficult to raise the fry? I had experiences with the Yellow Panchax (now, third generation is spawning).

Please update us on the fry, Bro Stormhawk, thanks a million!

[Shi Xuan]

Hi piperon,

Thanks for the wishes and same for you, may you have a bountiful year ahead.

The Rivulus wasn't really free, I exchanged the eggs for a female Aphyoplatys duboisi, initially with the thought of pairing it up with a male but I ended up with a trio instead, but it's good... just have to wait for the younger pair to mature before spawning them.

They are an easy fish, considering that the newly-hatched fry are fairly large to begin with. I still keep the adults and they are really prolific, but I'm not breeding them anymore because I am making space for the labyrinths, so now, they share a tank with some Oryzias woworae and Pseudomugil gertrudae.

[stormhawk]

The fry are fairly simple to raise. I just kept them in a tank with algae on the sides and fed them live Daphnia/Moina from the start. For most of the time they just ate whatever zooplankton was available in the tank. They were able to handle the smallest ones early on. However they are a little slow-growing as with all Rivulus fry.

[piperon]

Thanks bro Shi Xuan and Stormhawk,

Thanks for the infos.
Pseudomugil gertrudae is definitely a beauty but I don't think I would mix with my yellow panchax cause their fins will be destroyed for sure.
I seen a video about the long fin killie fish, check it out at http://www.youtube.com/watch?v=Z5bSsAY5MEo

[Shi Xuan]

Yeap, gertrudae is a true beauty and especially stunning against a dark background and the males "flaring" with one another. I have two dominant males, one sleeper male and a female but I think a pair is enough, because they are prolific spawners.

I wanted panchax but being a surface dwelling fish, I wouldn't keep them in my current setup because I don't have enough tanks and the bigger tank is uncovered.

[piperon]

It is definitely truth and a must to have small wiring hole cover for keeping panchax (they are extreme high jumpers, just like the anchor fish).
Although I had placed a plastic cover with 5cm size and yet I lost one female jumping out.
Now, I double protect the top with one more barbecue metal cover. Hahaha!

Thanks for the update and enjoy your weekend.

[stormhawk]

Dinner is served:



Close up of the critters:



After several days without live "boon", bad BBS hatch and just Infusoria and powder crushed Hikari Carnivore Pellets for food over the past few days due to the CNY period, the fry get their long awaited buffet in the form of cladocerans aka Daphnia/Moina.

Apparently there are bits of some sort of algae too in the "soup" that came with the live food, which becomes food for the 2 juvenile cherry shrimp in their nursery.

[stormhawk]

After 2 weeks:


Taken on 18th Feb


Same fry on 21st Feb

Apparently they're able to handle the smallest Tubifex worms. According to the best site on Rivulines online - www.itrainsfishes.net - by Frans Vermeulen, this species matures at around 4-5 months of age. No wonder they're slow growers.

I thought I wasn't feeding enough "boon" aka Moina to get these babies biggers. The runts in the group are still small.

[stormhawk]

Week 3:



They are now able to handle regular size Tubifex worms. Very skittish now. They react to every single movement near their Satellite box.

[Shi Xuan]

Yeap, this fish is very skittish. I hardly see them even in a 12L tank, let alone a 60L tank where they have plenty of places to hide. When stressed or cornered, they will spy hop like all Rivulus do, so their tank must be tall and they will spend most of the time at the bottom of the tank. I must say, their behavior is exactly like a betta... convergent evolution, I guess?

[stormhawk]

I guess so, but if I minimise my movement they don't scatter all over the place. By the way, I thought I had 7 fry initially, to my surprise, I found 9 in total.

Out of the 9, 4 have kinked spines, the rest are normal. I thought it was something to do with vitamin deficiency, yet their 5 siblings are normal.

[Shi Xuan]

It happened to me too. The fry came from my adult breeders without any visible abnormality yet their siblings are deformed. I culled the lot away and keep those without any problems as my breeders. Just avoid using the ones with kinked spines to spawn and note down your observations to see if selective breeding over a few generations works to get rid of the problem.

[stormhawk]

If I get a skewed sex ratio I know who to turn to. Anyways, had a pleasant surprise. I was messing around with one of my Moina muck tubs that I left lying around. I thought I saw some live Moina, which I did, but apparently some freshwater rotifers, probably Brachionus calyciflorus appeared. This is the first time I ever had any kind of rotifer, so it was kinda cool. They react to light much like Moina do, but their movement though the water is a smooth gliding motion, unlike the jerky Moina. Now I need to find me some Chlorella tabs.

[stormhawk]

Week 6:



They are slow growers indeed. This is the largest one, about 3cm in length at the moment. Left with 8 individuals now, 4 normal, 4 with kinked spine. I have no idea where the 9th fry went to. Probably was a runt and died in the breeder box, no idea. They are still on a staple diet of live Tubifex augmented with live Moina every few days. A ball of Tubifex in their container can last for a week.

[Shi Xuan]

That's a nice fish you have there. I would keep the 4 kinked spine but not for breeding. Probably because of their slow growth, there's very little size disparity, unlike what you tend to see in Annuals, still you have to keep a lookout for runts and separate them from their larger siblings.

[stormhawk]

I found the escapee though. The missing fry no. 9 was in my main tank all along. Apparently it managed to squeeze out though a small gap and dropped into the tank below. Anyway, it's a kinked fry so I won't bother trying to catch it out for now.