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Hello, has anybody of you experienced problems with the fertility of eggs in the "laser" Corydoras?

I bred Corydoras green laser briefly, about 10 years ago, and I remember that the results were dismal, with barely 50% fertile eggs.

On Wednesday, I set up a new 210 liter tank exclusively for Corydoras (8 reticulatus, 8 leucomelas, 6 robineae, 4 green laser). On Friday, I bought 3 Corydoras orange laser and on Sunday, I observed that green lasers and orange lasers started to spawn together. They behaved like if they were a single species - orange laser males mating with green laser females and vice versa.

https://www.youtube.com/watch?v=VEFUzkP8A5Y

Therefore, I was very curious what fish I would get from this mixture. I counted 150+ eggs, which is very good, but only about seven are fertile. I was not very optimistic but this is a much worse result than I expected.

It seems that I am not alone in this regard because other people also experience problems with fertility.
https://www.irishfishkeepers.com/forum- ... ry?start=0

The first thing that comes to one's mind is temperature because it could hamper sperm activity. I had only 22 C (71 F) in my tank but other breeders explicitly recommend cool water for these Corydoras.
https://www.tropicalfishforums.co.uk/in ... ic=34775.0

Therefore, it is a mystery. Maybe, next spawnings will be better but it is understandable that preventing these problems would be wiser.

I wonder if anybody visits this forum at all? My YouTube video with the spawning of green lasers has 6 views so it is clear that nobody even bothers to read what I wrote.

The second spawning of my laser group (on Wednesday) produced 77 eggs but again, 0% are fertile.

As I don't know much about Corydoras, and dislike looking at You Tube, I did not follow the link.

I did read, however, what you wrote.

I was one of your YouTube views. I like corys a lot. Unfortunately, I've never kept any of the lasers, so I can't speak to your question.

But I would advise you to separate the green from the red lasers. They are different species but they are close-enough related that they might ty to hybridize. (that might explain your eggs failing too).

First rule of keeping corys to breed them is don't keep two species in some cory lineage together.

Good luck with your fish. They are pretty species.

Cheers, Eric

cartouche wrote: ↑19 Mar 2020, 09:01 I wonder if anybody visits this forum at all? My YouTube video with the spawning of green lasers has 6 views so it is clear that nobody even bothers to read what I wrote.

The second spawning of my laser group (on Wednesday) produced 77 eggs but again, 0% are fertile.

Hi,

I'm sorry you feel that way. I believe that if someone read this or any other post and have noting to say, they will simply not write. I don't have green lasers, therefore I have no experience with them, so I didn't write. I do have C. Aeneus & B. Splendens. Last year the last clutch of egg the Splendens laid were a dud. Not one egg was viable. Other wise I had great success hatching them and no so much after that just 9 made it to adult.

I have no idea why this happened but since it was the last one maybe the males dried up and was looking forward this year but non of my species spawned. My location is the factor, the temperature doesn't go as low as they need and I have not chillers yet to help them.

Regards,

Raamses

I cannot be 100% sure about the cause-and-effect but I kept the temperature warmer (23-24 C) and the last two spawnings had about 70% fertility rate. Really a huge difference! The fry hatched very well, even in tap water with 9 dGH and alkalic pH close to 8.0. Again, a big difference when compared with the advice of other breeder, who recommended soft and acidic water.

Have you moved since last pawn, if not, is there a new treatment station or maybe they have changed the processes at the treatment station? So the parameter are all out of whack. Also is this the first spawn for this specific group of corys or have they reproduced before? I think it could be that in the group you selected for breading you may have only one male and by chance it is sterile? Because after going over what you have said. It's the most probable reason and I believe you have may a cory shooting blanks my friend.

I don't know what you mean under the term "treatment station". In any case, since I raised the temperature, they have been spawning without problems.

cartouche wrote: ↑05 Apr 2020, 11:26I don't know what you mean under the term "treatment station".

I suspect he means municipal water treatment facility.

cartouche wrote: ↑05 Apr 2020, 11:26In any case, since I raised the temperature, they have been spawning without problems.

Glad you found a solution. Much success going forward.

Cheers, Eric

Hey, I'm glad I was wrong. Congratulations on the spawning!