Sexing Purple Firefish

[jejton]

After being in quarantine for 2 weeks or so, I decided it was time to introduce my 2 purple firefish and 1 shrimp goby to my DT. They were all eating, looking and acting healthy so I figured it was all good. There was a difference of about .01 or .02 in the SG ( DT was lower ) between the two tanks. I couldnt find my spare airline so I put the fish in a bucket with just enough water from the quarantine to cover them and then added about a cup of DT water every half hour or so for a few hours. They looked ok, though one of the firefish would lay on its side a little at times but I thought it was due to the shallow water. When I introduced them to the tank they immediately swam about until they found an area they liked and even ate immediately when the tank was fed. This morning I found one of the firefish dead and being finished off by shrimp and mini serpent stars. Very upsetting as it was a beautiful fish and the two seemed to be a pair.

A.) Where did I go wrong?
B.) How can I sex them so I know which one I lost as I'd like to replace it.

 

[Deanos]

My research seems to indicate sexing Nemateleotris decora to be nearly impossible.

 

[aznt1217]

What kind of shrimp was it... and also maybe the other firefish took it out.

 

[jejton]

nah, i dont think the shrimp or the other firefish took it out. the firefish were getting along just fine for two weeks in the quarantine and werent fighting in the DT either. The shrimp havent attacked any fish either. I must have screwed up the acclimation and the shrimp ate it when it died.