what's wrong with my Cardinals?

[rubyjess]

hi
i have a 180 litre tank which was fully fishless cycled took about 4 weeks
i added numerous fish overtime
11_now 6 cardinal tetras
1 betta deceased
4 bentos tetras now 3
4 corys
1 plec
2 bolivian rams
2 clown loach
the betta died fron what looked like a fungal sort of infection as did the 1 bentos tetra
my concern are the cardinals they are dropping like flies,3 have whitespot which is going to be treated today with medication ,which is best and most affective?
most of the surviving cardinals are sitting on the bottom of the tank
all of the others are doing great and look very healthy
why is it only affecting the cardinals ?
any advice would be great thanks

 

[dkpate]

It might be affecting all of the fish, but you can't see it. I would recommend raising the temperature to 86*F, and leaving it for at least 10 days. This speeds up the ich life cycle, and doesn't allow it to reproduce.
If you go the heat route, you will need to add an air stone or lower the water level, since warmer water has less oxygen