I’ve had two Mollys for a long time and they recently had 4 babies that grew pretty big... yesterday I removed them, put them in a bowl with water from the original fish tank, drained and cleaned the fish tank, filled it with tap water (which I always do) and put the fish back in the tank once the temperatures matched exactly. Today all 6 Mollys are dead! what could’ve killed them? The tank was getting really nasty before I cleaned it... I thought getting all the junk out would be healthier though... what went wrong?
