[cichlidgirl1]

I was curious if you can vent oscars to tell male from females. I keep fronts and we can vent check them to view small differences in the opening where the tubes come down. just curios if you can do this with oscars. I rescued two oscars yesterday and one of them has a tube down . The other one herds it around and does some tail slapping and flaring but never bites .

 

[Blu-ray]

I had drawn a pic to show male and female tubes. I tried to show all possible cases for tubes. in my experience it has worked for oscars and some american cichlids like RD, FH, BP, GT.
for my pair of oscars, male tube is always down but female tube is visible only at the breeding time that is like the second case in the pic. in normal time its like the first one.
here is the pic:

that my theory, it may not be easy for others to use it :lol:

 

[cichlidgirl1]

Thank you, i can use that. Very helpful. Also how often do you experience the female to be the more aggressive one in a pair, herdiing a male flaring at a male etc.. ?

What would you make of these two vent areas ?
This appears to be the dominant fish, it herds the tiger around, doesnt bite it but herds, the tiger follows it.

This fish swims around with a small pointy tip pointed towards the tail area. This fish is subdominant. Its the tiger oscar. According to your chart it has the male organ in pic 1.

 

[Blu-ray]

well its getting so hard
this is the correct link for your second pic :
http://i238.photobucket.com/albums/ff186/amandas_photo_2007/oscarventing022.jpg
I can't say anything for sure. one that has pointy tube toward the tail should be male but in the pic it seems too wide and big like a female tube, can you take a side view shot?

for the dominant and subdominant behavior, if they are male and female usually the male should be dominant and excite the female to lay eggs but here we don't know they are male and female or not, may be both are the same sex.