Help With Strange Deaths

My water quality is consistently perfect. No nitrates, nitrites, or ammonia. All water was pre-conditioned carefully before being added to the tank. I had only one male golden wonder killi and two females. The tank is a 10 gallon, but the killis are not entirely full-sized, so they have space. The females have died off one by one. At first they look fine, then they become lethargic, then can't seem to balance their swimming properly, and as soon as that symptom appears, they are gone within hours. There is no eating problem, they will eat even as their health declines. I had them on flakes, mosquito larvae and frozen blood worms. The pH is very alkaline, but as I understand from various care sheets on Golden Wonders, a pH from 6 - 7.5 is acceptable.

Note: The male is incredibly healthy, active and aggressive. He courted the females so tirelessly that I had to separate them. It wasn't until weeks after I had done so that the females began to die. They were separated by a perforated in-tank aquarium divider that I got at the pet store. I rotated the male and the females from one side to the other once in a while. There was no external evidence of disease or parasitic infection and no obvious digestive problems. Females were always passive and peaceful so there is no chance that harassment was responsible for either death.

I am completely frustrated and very upset by these losses as I was attempting to breed them, which I read was a relatively easy process with this type of killi. I also read that they were extremely hardy as they exist in a wide variety of conditions in the wild. In fact, they can thrive in both fresh and brackish water. So tell me! What on earth went wrong? What haven't I thought of??

[RonWill]

I'm stumped too because panchax are very hardy, provided they don't jump out of the tank. The only thing I can think of is TDS shock (Total Dissolved Solids) and IIRC, Wright did mention that if the difference is 3 times, you can almost be certain that the fishes are goners. Did you measure the TDS in your tank and the shipping water? Just a thought.

If you're fortunate to acquire additional specimens, these will spawn readily in mops, just like Blue Panchax (Aplochelius panchax). Good luck and keep us updated.

In case you didn't notice, most of us sign off with our names and it would be nice if you can do the same. BTW, where are you from?