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I don't wish to make a long thread out of this, since there are already a few other threads about (Search results for diphyes in the forums), but I wanted to share a video of my new fish spawning while in quarantine. Spawning was videorecorded at midnight, but was mostly finished shortly thereafter; I must have caught them right near the end of their spawning behavior (or it stopped because I disturbed them). Posting video here so that it's not stuck back in the "What's my catfish?" forum with my original post (Mystery cory at LFS? And spawning in quarantine!) requesting ID for these new fish of mine.

Cheers, Eric

Corydoras diphyes spawning/egg laying

Another round of egg laying, this time only three nights after the first spawning. Much smaller clutch this time, only about 30 eggs overnight last night, this time about half on glass (mostly along corner silicone) and the other half in Java moss (similar to first spawn). I popped a few accidentally as I scraped them off the tank walls, which makes me believe these eggs are more fragile than aeneus eggs. Some new eggs today look off-color again, perhaps not fertilized. In total, I have 90 eggs, 64 old and 26 new, now incubating with Ramshorn snails. I didn't count the number of bad-looking eggs, but I'd estimate them to number in the range of 10-25 out of 90. None of the older eggs, now approaching 4 days old, have fungused and none have disappeared, so Ramshorn snails are doing their job (controlling fungus without eating eggs) properly. I would imagine that at almost 4 days old, these older eggs should be about ready to hatch!

Cheers, Eric

Cool video! I have my camera handy so I can try to get a video if any of my cories actually start spawning. I've seen my C. aeneus and C. sterbai go through the motions numerous times lately, but no eggs yet. My C. pygmaeus have been acting frisky too, but can't tell if they're going through the motions or not cuz it's always at the back of the tank. I'm starting to think my water is too hard and alkaline in spite of my best efforts to soften it and drop the pH. Might hafta look into an RO unit for my SA fish.

Ivan

Wyomingite wrote:I've seen my C. aeneus and C. sterbai go through the motions numerous times lately, but no eggs yet. My C. pygmaeus have been acting frisky too, but can't tell if they're going through the motions or not cuz it's always at the back of the tank. I'm starting to think my water is too hard and alkaline in spite of my best efforts to soften it and drop the pH. Might hafta look into an RO unit for my SA fish.

Although most of my tanks are between pH 6 and pH 7.8, I've had Corys (aeneus, trilineatus, and Scleromystax barbatus) spawn in the low pH 5 range too, and trilineatus recently spawned at pH 4.5. And water ppm anywhere from 50-450 ppm. My species are pretty flexible.

Besides a cool temperature water change, the most significant trigger I have for spawning is a few days of feeding them live Tubifex worms. Feed enough worms at once that some of them escape into the sand or gravel bottom. That way the corys can continue to graze on these like a cow eating grass. After a few consecutive days (or nights - I think my corys get more food when I feed them at lights out because mine are pretty shy) of live worms for food, my aeneus and trilineatus breed like clockwork.

Cheers, Eric

These cats won't stop! Two days after the second spawn, they spawned again today. All new eggs (32) were laid on glass, none in Java moss this time; another difference is that this third spawn occurred in daylight or early evening, instead of late at night.

Total after three bouts of egg-laying over 5 days, approximately 130-135. The oldest eggs should be hatching in the next 24 hours, based on other breeding reports.

My only disappointment is that I broke my favorite plastic ruler, which I use to scrape eggs off glass and measure all my fish.

Cheers, Eric

bekateen wrote:Re: Mystery cory at LFS?
postby bekateen » Thu Mar 17, 2016 10:44 am
I know that corys really like to swim in groups; I feel bad that there were only two in the shipment, but I'm glad they appear to be boy and girl. I'm not sure how well they will fare in my house, given how warm it gets in the summer. But there are solutions to that.

In regards to having only two, I know rmc has some extra for sale if I want them. But this also represents a challenge: I guess I'll just need to visit the LFS more often and keep checking their future shipments!

2 Corys: one male, one female and a spawn within weeks, that's a fast way to get a small colony of tens of them without spending days "to visit the LFS more often and keep checking their future shipments!" ;)
Congratulations!
Cheers,
francois

francoisMtl wrote:2 Corys: one male, one female and a spawn within weeks, that's a fast way to get a small colony of tens of them without spending days "to visit the LFS more often and keep checking their future shipments!" ;)

Thanks Francois. By coincidence, I collected another 70 eggs this evening, bringing the total number of eggs laid over four spawns to ~200. The only setback was that the fertilization rate was very poor in (at least) the first spawn: Only half of the first 60+ eggs hatched. The newer clutches appear to be improving in fertilization rate; practice makes the parents better.

Although I could make a colony really quickly with all these babies, I would rather prefer to sell all the fry so I don't end up in-breeding F1 fish with parents or with each other. So in fact I'd still like to find a few more adults at the LFS so that mine can be happy in a bigger shoal, rather than just the two of them.

But more than that, now I "have the bug" to regularly check these new shipments, to see what other oddities show up. Who knows, maybe I'll find some of those stunning that have the striking black-and-white colors and dorsal fin extensions (I know - wishful thinking. LOL).

Cheers, Eric

Here's a macro pic of new (today) eggs:

Corydoras diphyes fry, 1 day post-hatching:

Not wanting to drudge up an old post, but can't think of a better place to put this: When I bought my C. diphyes, I learned they are a cool-water species, preferring water temperatures in the mid 60s to mid 70s (degF).

As I've described elsewhere (How do you do a "cool water change" to stimulate corys and plecos when you've got this?!?), I was recently in a week-long heat wave. Throughout this, my tanks got very warm, with overnight low temps in the upper-70s. I was concerned for the welfare of my fish, because a year ago I lost an entire breeding group of six adult under similar weather.

Well, I'm glad to report that this didn't seem to harm my C. diphyes. Not only that, without any effort on my part, the two parents have continued to spawn throughout the heat wave (not big spawns as far as I could see, maybe 1-3 dozen eggs each time) and the fry are growing in the parents' tank.

I report this just so others know this species is able to handle these higher temps, even if they aren't optimal. I wouldn't recommend that buyers start with this species at such high temperatures, but if the fish are forced to acclimate to warmer temperatures over time, I think they'll be okay.

Cheers, Eric