My eyesight must be that bad

I picked up what I hope to be my first bloodstock pair of Banggai cardinals 2 days ago and so far so good. They eat frozen enriched artemia, frozen mysis and will nibble at spectrum pellets 4 times a day in the 15gal tank I have them in.

Now I've read and reread all the info I could find on sexing them with the venting method. I had the seller feed them prior to making my selections so I could do my best to select a male/female pair. From what I could tell, one fish has two distinct vents while the other has more of a single vent with like two knobs, with the posterior knob being a little larger and more noticeable. Keep in mind I can barely see anything even when they are full to the point of bursting on mysis and artemia. They do not stay still and the vents are hard enough to see to begin with!

Based on my best observation, the male appears to be the bigger of the two at about 2" while the female is just a tad smaller. These two fish literally ignore one another constantly. They drift around making simultaneous darts towards potential food items the go by but that's the extent of their interaction in 3 days. At what point would they become aggressive if they were the same sex? Obviously they were added at the same time so no fish feels more dominant. If I'm right and the male is the larger of the two, does this matter? I've seen no mention of size ratios in successful pairs.

Thanks in advance guys,
I'll work on getting photos of their vents.
Joe

Sometimes opposite sex pairs ignore each other for awhile especially when added to a new tank, so I wouldn't worry just yet. Mine ignored each other for a month then suddenly spawned one day. Get pics of the vents if you can, but honestly, if they aren't outright trying to kill each other, you're good. 

Wow so you really think they would go at the fighting right away within the first several days of being introduced to the tank? I figured they would still be in that short breaking-in phase where they aren't confident enough to really start picking fights.

I tried getting pictures of the vents tonight at their last feeding before lights out but no luck. Will try again tomorrow.

Joe

I've never been able to see the vents either and yes, aggression usually happens pretty quickly. IME 

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

Ok cool, that pretty encouraging actually.

Thanks guys,
Joe

I've found two females will happily coexist.  Although I've also found that the majority of fish I've seen in LFS over so many years are male, so I've often ended up with two males in which case I've found they will usually start fighting within just a few days.  I've oft wondered if there was a greater number of males born in the wild (and maybe in captivity too) than females to create more potential incubators.  Since papers suggest that Bangaii are not monogamous in the wild, this would make sense.

Don't let fear and common sense stop you! =]

I too noticed that there were more definitive males than females, using the venting method. Assuming this was a coincidence, I took several days and multiple trips to a few different retailers to pick my fish. What I've found is that in still photos like those you've posted, I can see the difference clearly, but on a moving fish it's a whole different story!

FWIW, identifying a fish as a male seems a lot easier than verifying a fish is a female as well. I saw quite a few 'iffy' fish that were likely female but could have also been males with poorly extended vents.


Joe

So after two days, nine feedings, and 500 pictures I've managed to get a single photo of each fish's vents that I can call half way decent. My only problem is they are on my iPad and I can't get the file attachment link to work.

Can anyone help me out here? I really want to get this done from my iPad because the photos are crappy iPhone ones and I'm afraid if I send them to my laptop the resolution will get worse.

Can you upload them to photobucket? Use the IMG code to post them from there.

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

I tried but when I opened them on photobucket the resolution had deteriorated and the vents are basically gone.

Just stumbled upon this article while looking for something else: http://www.advancedaquarist.com/blog/how-to-determine-the-sex-of-banggai-cardinalfish

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

Is it fair to say that females too show two vents, but that their anterior papilla is significantly smaller than their posterior one; while in males, both papilla are equal in size and a bit further apart?

The only thing I'm sure of, having observed easily over 100 well fed fish in the recent weeks, is that there are two definitive vent shapes. The 'male' shape is two clearly separated papilla. The 'female' form is more like a single papilla with an anterior, almost insignificant bump and a posterior, more pronounced bump. If this description sounds accurate to the more experienced breeders please let me know. All I have for photos is my iPhone so there isn't much I can do by way of pictures because of photo quality but I'm pretty happy with my description lol

I purchased a second pair about three days ago abiding by my above differences. They are not fighting. They mostly ignore each other, sleep near each other and occasionally, mostly during feedings, the 'male' will chase her a bit, but nothing crazy. This pair is a bit less mature than my first one, being captive bred, but there is a marked difference in the appearance of their vents.

Also, idk if this matters but the male is slightly larger than the female. Does this matter?

Sorry for the long post
Joe

Any updates

Michelle  
 

Haha funny you should ask...I gave the pair to a good friend to take care of for a while so I could sort out housing for some various other fish pairs. This was about 3-4 months ago and about 3 weeks ago the smaller of the two began furiously attacking the larger one.

The larger was the one I'd decided was the male and the smaller I was sure was a female. They had lived together since the first week of April and had been fruitlessly displaying to one another since about early May. They rarely were more than a few inches apart even in his 120gal reef. This behavior continued until a couple of weeks ago when the 'female' turned on the 'male' and finally killed him about 4 days ago.

I'd instructed my friend not to separate them because another friend of mine who'd been successfully breeding them for months now said that part of their pre spawn behavior often included such aggression.

Sorry for the sucky update lol