Mollies are dying 1 by 1

Question
I have recently set up a tropical tank, 2 x 1 x 1  feet in size. I let the water settle for weeks and then added a few cherry barbs who are are still heatlty and been in there for 3 weeks. 10 days after the Cheeries i added 5 mollies, 3 females and two males. This weekend a male started hovering at the surface and then sank to the bottom and died withinn a few hours. Today the same happened with a female? They seem very happy and active and then suddenly go down hill very quickly!
Any ideas what i'm doing wrong?

Answer
hey Paul!
could be a few things wrong lets go through the steps to check and make sure your tank is suitable for the fish.
by the dimensions it sounds like a 10gallon fish tank if your fish go over 1" per gallon that's a main factor.
second the temp should be around 25 to 28 degrees Celsius.
third double check ammonia and aggression.
fourth always look at the tank quality from the store you are buying them from check for dead fish, stress, how active they are.
may just be a bad batch from the store.
so go over those four things and check back with me.

have a good one!