Normally,Just the fact that you are buying fish is stressful to the fish themselves.Afterall,They have to travel to get to the Pet stores,and not always in the best conditions. Once they reach the Pet Store,they're unbagged,and put into tanks-which is another change for them. Then ,you come in and buy them & they're bagged up again for you to take home.

That is sure alot of stress for a fish,so sitting in the bottom of a bag could be normal. The most important thing to remember about new fish,is that they don't always come from a tank which matches yours in PH/Nitrites/Ammonia/NitrAtes,etc. so you have to slowly acclimate them to your tank water.That does not mean taking the fish bag and floating it in your tank water,and then releasing them. Ph is a big factor right off the bat. Putting a fish into a lower Ph than what it is currently swimming in is very dangerous,. In order to do it safely,the best thing to do is to add your tank water Slowly to the water that they are in over a period of a a couple hours. This keeps them from going into PH shock-which by the way,kills alot of new fish. People just kind of plop them in not realizing what a difference there could be between the two waters. Maybe this will help your future fish,eh? I'm glad to hear that the fish are doing better-Good luck!