Sexing a 4" bloodred RedDevil...is it possible?

[danny2875]

yeah you can never go by the fins or trailers on rd or midas.

 

[Mattyou]

If you have a female anything put it in with the new fish. At that size if it is a boy he will let you know.

 

[fwlion]

only surefire way to tell is to vent it

take the fish out of the water turn it up side down and look at the tube right passed the anal opening if its triangular in shape its a male if its square are just big and rounds its female

 

[Japtastic]

There is some info on flower horn venting here, I'd presume it's the same for any fish?

http://www.monsterfishkeepers.com/forums/showthread.php?t=182843

Just scroll down a little...