another knight goby?

[tanhql]

as people here might already know, my knight goby is hiding in its cave 24/7, with me target feeding it. i was wondering: can i put in a male knight goby with it to make it more lively (i'm suspecting it is a female), because i didn't add it to the tank for it to hide 24/7. it's a 20g brackish, with the knight goby and a f8 puffer. nitrates are around 10 using purigen and mini rdsb.

below is a photo of the knight goby before it went hiding.

thanks.

 

[GuiltyPleasures]

It looks like a male knight goby to me, I have two in my brackish setup and one looks like that one, and the other (female I believe) looks different, less spots, doesn't have that cool top fin and isn't as white as the male one. My female hides more often and also like to stick to the glass, but the male swims around the tank most all the time like my other fishies. Hope this helps some