My Delphax Are Dancing

I only have 4 corys in the 29g now. (and 2 cardinals)
I have 3 delphax and 1 lonely napoensis. I have been hunting more with no luck. Any way... I took the other corys from this tank to the store 2 days ago. Now today I see the delphax out and dancing. I have been trying to figure out what sex they are for a while, but I can't tell. Since they are dancing... does that mean I have both? Will they dance if they are all the same sex? I have not seen eggs yet.
Here are a couple of pics of the 4 of them.


Can you tell what the sexes are of the delphax?
I know the napoensis is a lady.
I also need to know if the two kinds can breed. Should I move the napoensis lady?
How do you know which kinds will breed with which kinds other than their own? Is there a rule to go by or something?

Thanks for helping me.

EDIT!

Infact I think im wrong haha!

Sorry, I tried to help but at 2nd glance im just as confused as you are!

Good Luck

Richie

There are different dances, imo, in the Cory world. The sexy dance is one. In that there is a chase going on as you know. But other than that, there are other variations on the happy dance. So happy can lead to sexy, but the Corys can be happy and dance even when they are not spawning.

I would say pretty sure that the Cory in the bottom pic across from the napoensis is a female. The one next to her is a male. My ill-considered first glance opinion. Hopefully there will be a vote from someone better at IDing pics.

Maybe.
If not I guess I will just have to wait and see if I get any eggs. Then I will have to see if the eggs are any good. They are still dancing so maybe.
From what I have seen so far... They may just be happy. I have not seen any one doing the head dance yet. They stop when they see me though so I can't be sure. I just see them zipping up and down all over the place from a distance.
They have stayed hidden ever since I got them a long time ago (except for feeding time), so I am just really glad to see them out. That is a major improvement.
I guess they just didn't like all of those other corys in there with them.
It would be nice if they would spawn though. Then Maybe I could get their numbers up a little bit. It would be great if they could do it themselves since I can't find any more like them.
Then I would just have the one to worry about.
Is there another cory close enough to the napoensis that I could get that she would fit in with? She tries to hang out with some of the others, but they just wouldn't have it... so she just stays alone and watches them. It is really sad. Would it work if I got some san juans to put with her? They look a lot alike. Or... would I just end up with more corys and her still be swimming alone?

R1ch13 & jollysue... Thanks for trying.

Hmmm....
Say your prayers. My San Juans just plastered their tank. I will either move the fish or the eggs. I actually want to move those fish, but I put the market pandas and lf bronze in the tank I want them in. I want to put my small people in with your new plants and the Galaxy Rasaboras. That would be the melinis, the arcuatus, the san Juans, the lps pandas and the LF pandas.

I will do what I get inspired to do, I suppose, and see what happens. So far I have not had a successful spawn with them since the big gal in the pic died.

It would probably do well with any Corydoras from the C. elegans group. Just make sure they dont interbreed.

As for the C. delphax, it looks like 2 males and a female to me.