Advice Needed for Breeding Sterbai Corydoras

[rross11]

Hi, I need some guidance in trying to encourage my Sterbai corys to lay eggs and breed.

I've recently moved a group of 12 sterbai from my community tank to a 100L set up, with a group of 6 males and 6 females. Water temperature is at 26 degrees celcius. The tank is scaped with sand, bogwood, plenty of java fern, amazon swords and valisineria, and has plenty of hiding places for the group.

I've been trying to condition the fish with regular feeding of Corydoras sinking pellets, brine shrimp, bloodworm and black worm. Feeding every two days, and have tried feeding worms either before or after a water change (nothing has encouraged them).

I do weekly water changes, with about 50% of water changed out, adding cold water to lower the temperature (I'm careful not to go too low as to shock them).

When they were in the community tank I saw no signs of the females developing eggs and it appears to be the same here in the new set up.

Does anyone have recommendations as to what I can do to encourage the fish to lay eggs and breed? Any advice would be greatly appreciated!

[Jools]

If the females are in condition, neglect them for a few weeks. Then start up your regime.

What size are the fishes, can you post a pic or two?

Jools

[rross11]

Hi, thanks for replying They're quite large, about 5-6cm? I've attached some photos to the original post

[Jools]

Great, and the fish look really nice. I'd consider spawning mops and/or java moss. Maybe the only thing missing is the spawning site.

For me, I'd lower the lighting and not have too much current - but that's fiddling at the edges.

Jools

[rross11]

Thanks, they're some nice chunky fish and I think the ratio of male to female is ok so they don't get too harassed?

I've actually got some java moss in there too attached to the bog wood, but could maybe add some more? (see photo attached - the rock's keeping the wood submerged).

Is there anything you would change with regards to routine, i.e. feeding, water changes etc?

I've turned the filter to quite low, but enough to aerate and maintain a slow current. Lights are on for 4 hours a day - potentially reduce this?

I just find it really odd the females never, ever, seem to develop eggs. Perseverance will out hopefully!

[dw1305]

Hi all,

Thanks, they're some nice chunky fish and I think the ratio of male to female is ok so they don't get too harassed?

I'd probably try and 2 : 1 or 3 : 1 males : female ratio.

I've actually got some java moss in there too attached to the bog wood, but could maybe add some more?

Definitely add some more it doesn't need to be fixed to anything, ideally you want a fairly large moss mass.

I've turned the filter to quite low, but enough to aerate and maintain a slow current. Lights are on for 4 hours a day - potentially reduce this?

I'm going to tell you that actively growing plants are the best thing you can have for improving water quality and plants need light, so I'd go to at least 8 hours "lights on".

cheers Darrel

[Jools]

Just on the lights, as I brought it up, agree with 8 hours, just not so bright or rather think about making it a little less sparse. I also have all sides of my tanks, except the front, covered.

[dw1305]

Hi all,

... or rather think about making it a little less sparse....

Definitely for me, I'm not a less is more person.

Cheers Darrel

[Mexnotex]

Hello,
Corydoradinae need to be environmentally stress to be able to procreate. If conditions are to their liking, they will not do much. Each species have their own idiosyncrasies according to their environment provided. What we do as keepers is only to provide them with a suitable environment for them to procreate.
Corydoradinae like a flow, no question. How much of a flow it all depends on the species. Also, try doing water changes 3 times a week, but only 1/3 of the tank.
What is the TDS? Preferably 120 ppm or less.
pH 6-7
Feed them twice daily and heavy on the protein. Morning BBS and night frozen or live worms. Only for a week and see how they respond.
Following week, give them a good quality flake, crumbled and presoaked and BBS. Too much protein is not good and worms contain a lot of protein. We are just conditioning the group.
Water changes once a week.
Third week you need to do a little twitching, maybe hold on the water change. If so, slow doing on the flakes but feed them protein, flakes will pollute water a lot faster. Feed them twice daily.
Fourth week, more frequent water changes and feed only once daily.

Hopefully this helps,
Martin

[rross11]

Just on the lights, as I brought it up, agree with 8 hours, just not so bright or rather think about making it a little less sparse. I also have all sides of my tanks, except the front, covered.

Hi Jools, so it's been a few weeks now since I moved the sterbai into their set up. And have been trying to condition them with a mix live foods, pellets etc; plus the water changes.

I've also added plenty of java moss to create a spawning site too.

The fish appear to be content, but still zero sign of any attempts at spawning or the females filling with eggs.

Any suggestions as to changes I could make to further encourage them? I'm wondering if reducing the number from 6 males, 6 females (12 in total) would be the way to go?

[Jools]

You don't normally need to do this but breeders of other families of fishes like characins for example keep males and females apart and then put them together.

Reducing to one certain male is a good shout - having six is an unusual set-up.

Honestly, try neglecting them for a few weeks then pick back up the excellent water change and feeding regime.

Jools

PS I've only bred three species of corydoradinae, so do take others views too.

[rross11]

Hello,
Corydoradinae need to be environmentally stress to be able to procreate. If conditions are to their liking, they will not do much. Each species have their own idiosyncrasies according to their environment provided. What we do as keepers is only to provide them with a suitable environment for them to procreate.
Corydoradinae like a flow, no question. How much of a flow it all depends on the species. Also, try doing water changes 3 times a week, but only 1/3 of the tank.
What is the TDS? Preferably 120 ppm or less.
pH 6-7
Feed them twice daily and heavy on the protein. Morning BBS and night frozen or live worms. Only for a week and see how they respond.
Following week, give them a good quality flake, crumbled and presoaked and BBS. Too much protein is not good and worms contain a lot of protein. We are just conditioning the group.
Water changes once a week.
Third week you need to do a little twitching, maybe hold on the water change. If so, slow doing on the flakes but feed them protein, flakes will pollute water a lot faster. Feed them twice daily.
Fourth week, more frequent water changes and feed only once daily.

Hopefully this helps,
Martin

Hi Martin, thanks for the feedback. I'm not sure of my TDS as I can't find my measure to hand. But I've tried to condition them with a mix of live foods and also quality flakes, with intermittent water changes as you suggested too.

I'm considering changing the number and ratio of males to females. Perhaps removing 1 or 2 males to see if this works? I suspect a group of 12 is too large.

Interested to know if you have any further tips.

Cheers

[Mexnotex]

Hello, Ross
Try to bring temperature 2C less. C sterbai can resist those temperatures but not for long periods of time.
Do water changes 3 times a week, only 1/3 of it at a time with cooler water, bringing the temp 4C down.
pH 6.8, TDS 120 or less. I
f your water is 200ppm and you can get a spawn out of them egg shells might be a little to hard for the embryos to break through. More minerals in the water, egg shells will absorb them, and the shells would get tougher to break.