I stocked my tank and loads of my fish died?

[Rosia]

I had a good stocked tank, but then they suddenly all started dying . So i did water tests ect and there was nothing wrong. So i emptied my tank (all fish were dead anywya) and let it cycle for 9 weeks.
I then went the fish store and asked what to get, they guy gave me about 25 diff fish!! Its only a 70l tank! I wasnt too sure but i thought hes trhe pro! Then 2 weeks in loads of them started dying!!
I now have 3 moliies, 2 gouramis, 1 swordfish, and 4 little tetras. Ive strted going to this new fish shop and they are really helpful! and told me id overstocked the tank! So i was wondering could i put anymore in? I think my mollies are pregnant also. Plus do i need a breeding pen?

Any help with why my fish kept dying wud be nice too!

 

[AidenG]

The reason your fish kept dying is because you had too many in there. Its kind of like a survival thing they die until the right number is reached. I know that most fish need a min of 2 gallons but the bigger the fish the more they should have i don't know about litters but another thing you have to take into account is what type of fish you have. How aggressive they are and where in the tank to they like to stay. like top middle or bottom because if you get all bottom fish then insted of moving up they will probably just die. So before you buy the fish look into some info on them and find a good balanced variety and you will get the best from your tank!