Is this true? How to tell male and female

[sajeevv]

http://web.cecs.pdx.edu/~davidr/discus/articles/sexingdiscus.html

[Allwin]

Only confident way of analysing the sex is examining their breeding tubes. None of the other way is proved enough.

[Second Hand Pat]

http://web.cecs.pdx.edu/~davidr/discus/articles/sexingdiscus.html

It is not reliable at all.

[Rudustin]

There is no other way other than to observe a spawning and even then that is not an absolute. I had two female checkerboards go through all the motions but they were both female.