Mass Deaths

Question
I have a large tank with a variety of fish in it, including Mollies, Tetras, Bettas, catfish, Loach etc... One of the female Mollies recently gave birth and as was inevitable, some of the babies were getting eaten, as did one of the smallest tetras, so I bought a small tank to put both the Baby Mollies & Tetras in.  I washed the tank, gravel & wood in clean water, put plants in & used the water from the main tank (which is regularly treated and changed) to fill it, thinking that if they were ok in the main tank, then it was safe to use.  All seemed well first of all, but 24 hours after moving the fish started dying off at an alarming rate.......the Mollie babies first, followed by the tetras.  I have a few thoughts on why, but I'd like to hear your thoughts too, if possible.  ONE.......I could have overfed them, bearing in mind I'm used to feeding larger numbers of larger fish....or does that not happen so quickly?  TWO.......could it be delayed shock from their move  ?  THREE....the pump in the new small tank (that came as an integral unit) creates a strong current. Could that be a cause  ?  

Answer
Hi Tim,
  Hmm...  1. Unless there is a bunch of rotting food in the little tank, that seems unlikely.

2.  Possibly but assuming that you were reasonably careful (and didn't leave them out of the water for 10 minutes or something like that) that seems unlikely.  

3. If you see the babies swimming frantically into the current, they could die of exhaustion but again, unless the current is really ripping fast, that seems unlikely.

I assume that no soap got into the new tank?

Using water from the main tank was a good way to go and should have made the transition very easy so it is puzzling.

Are there any signs of ick in the main tank? (ick can be very brutal on young fish).

-- Ron
  rcoleman@cichlidresearch.com
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