So as I have posted before, we were having a bit of an issue with an overabundance of fry from our live bearers. Last weekend we finished Operation Segregation by moving all the fry we could catch, like 40 or more of them, from our big tank to a new 15 litre that has had nothing in it but the fry yet. The oldest of the fry were hitting the month old mark and we really figured sooner rather than later would be best to get them out of a tank that is now (in the way of live bearers at least) an all girls tank. The 15 litre had been set up for maybe only a week or so but having tested for ammonia, nitrate, nitrite and pH all seemed reasonably well.
A few days later we also moved out female black molly in there who was quite visibly ready to drop and was being really aggressive to everything else that moved in the tank including the 2 silver sharks installed as the goon squad to help with the fry problem. We figured that it would be easier to catch her after and move her back to the big tank than try and catch all the fry again. So far, so good.
But this morning we woke up to find almost all of the fry dead (all but 2 to be precise )and lying on the bottom of the tank, and the molly is now no longer pregnant but not there is no sign of even a single black molly baby anywhere in the bunch! Very, very sad. I expected some loses but all of them?? Where did I go wrong??
Did you test your water again today? Were the fry missing or dead in the tank somewhere? Other than the cycling, I'd you have airstone in there? I try to keep one going when more fry build up in their tank. I don't know of mollies can abort like guppies can. If so, they'd be hard to find since they're so small.
Actually, I didn't think about testing the water today before I dumped it. Really wasn't thinking. But no, there is no where they could have hidden, there was nothing in the tank, not even substrate. It was only supposed to be a temp thing for a week or so until we could sex and sort them.
What about the filter in the new tank? Was it established? You likely caused an ammonia spike by adding so much live stock at once. Sounds like there was not an adequate amount of beneficial bacteria to break down the amonia.
It could be, Krazy. This was the first time there were any fish in there, and I did add a lot but I hoped that since they were all so tiny it wouldn't matter that much. When I tested the water everything came up fine but maybe it couldn't cope. Just want as much advice as possible so this doesn't happen again.
When you say it all came up fine when you tested - did you also test for nitrates? If everything, including nitrates, was at 0 then I suspect it tested fine because at that point there wasn't enough ammonia to show up, but that a few days later it had reached lethal levels.