Ive got mine for 3 weeks now, all 12 of them are still alive and kicking =)
No diseases what so ever.
The only problem I have atm is that one of the smallest is not accepted in the group.
The other ones attacked him and he is now blind in 1 eye.
I doubt that one will survive, but the other ones are all healthy.
With these fish you need to make sure you don't buy them to small.
Because when they are too small they are indeed very vulnerable for all kind of diseases, especially fungus types.
They also need to be kept at a high enough temperature, though not every source I read confirms this.
I have mine at 28°C and I dont see any problems.
I don't know why yours would have bloat. I can't help you with that, im sorry.