all my rasboras are dead... what the *beep* happened?

hey guys....

as I got up today and went over to the tank to give my rasboras their daily flakes, I noticed that one of them was floating upside down at the surface, dead.... one who was just barely alive was floppings next to him.... a quick search through the java moss revealed victims number 3 and 4....

It all happened last night, apparently, with bascially no warning, except that last night I noticed they were swimmig slowly in one spot at the surface... it looked strange, but they were otherwise healthy looking so I ignored it... I just cant figure out what happened. there are no obvious marks or spots anything on them, the bodies looked perfectly normal.... parameters are fine, and my betta looks perfectly healthy and is swimming around as usual. the only lead i've got to go on is the possibility of a swim bladder disorder... 3 of them were pretty old and were a good year or two of age, but a new, young one I just got also fell prey to whatever this is, so im pretty sure it wasn't just old age.... does anyone have any idea what happened here? im really bothered by this.... they were valuble members of my community for almost 2years.... I was actually thinking about downgrading to a 2.5G for my betta, I guess now i've got nothing to stop me...

Dwarf Puffers said:

Sorry to hear that . Was there anything in the air that could have leeched in? Is the betta acting differently? I don't think it was old age either, as 2 years is still pretty young for most fish...

Click to expand...

no, all I did yesterday was add more water that evaped out, and I added it from a 100% detergent-free pot that I use for my own drinking water, as well as for WC water for my 10G.

everything else in the tank, including the inverts and the betta, are perfectly healthy and acting normal. the parametere are exactly 0 ammonia, 0 nitrites, and 0 nitrates (they are 0 because my tank is very heavily planted, so the plants devour any nitrate that appears)I have not had any guests in the house recently, nor habe there been any contaminants near the tank. my mother smokes, but I make very sure that when she does, she smokes nowhere near the tank, and that none of he smoke goes over there. the new fish has been in there for 10 days, he came from a healthy tank from a trusted LPS from which I originally got the 3 other rasboras. the betta has bult a bubblenest and chased them away if they got too close to it, but he nev er directly attacked them or was overly aggressive. They were also far too aglie and fast for him to catch.