Sexing Red Firefish Gobies

[Acefspds]

I was wondering if anyone has any tricks or knows how to tell the difference in male and female Firefish. I just picked up a couple wanting them to pair. While I was looking them over I noticed a difference. One had what looked like a split dorsal.

Here is a reference pic (not the actual fish)
http://www.flickr.com/photos/cattanach/5641788892/

Here is a pic of what the other looks like (not the actual fish)
http://www.google.com/imgres?hl=en&...126&ndsp=19&ved=1t:429,r:9,s:126&tx=109&ty=65

If anyone has any experience or has read something I havent please let me know. I have read there is no way to tell, I have also read that the dorsal fins are the way to tell. I am just trying to confirm if possible.

 

[MCCOOL]

Firefish are not sexually dimorphic, they look the same. The split dorsal is most likely from another fish picking at it.

 

[Acefspds]

Firefish are not sexually dimorphic, they look the same. The split dorsal is most likely from another fish picking at it.

There is no other fish in the tank. Just them.