Tetras in warm water

I live in south east asia and the temperature range in here :26-34 celcius.
Inside my room the temperature always stay 30 celcius and 29 celcius at night
I have 2 fish tank ,first tank I have discus and some cardinal tetras.The second tank I got some albino corys with neon tetras.

I'm always wondering,Does it stress any of my fish?

 

That temp is too high for the neons, and they'll have reduced lifespans at that high of a temp.

I would stock with warm water tetras like rummynose.

 

It shouldnt bother the rest of my fish right?. Looks like I need to buy chiller for neon tetras

 

You could do that, but it would be easier and cheaper to swap them out for a warmer species.

 

what kind of tetras could stand my tank temperature?

 

Rummynose would be a good choice.

 

I saw rummynose on my LFS got so many white spot.Would cardinal do any good?

 

Cardinals are better than neons, yes.