fish not active

Question
QUESTION: We recently set up a 10 gallon tank with 3 fish in it:  a guppy, a ghost catfish,
and a red fish I think is called a molly.  We have changed 1/3 of water about
every 10 days, and have kept the chemicals in satisfactory levels altho it has
been hardest to get the ph to remain in the ideal range.  Last week the guppy
died after spending time on the bottom.  Now the molly is staying in the TOP
back corners of the tank, usually behind the heater, and right now with his
head up.  When we feed them once each morning (Tetracolor tropical flakes)
and only then does the molly become active,  both the remaining fish eating
by excitedly skimming along the top surface.  The ghost catfish seems fine,
but we're worried about the molly.  Also, soon we will have to leave for a
week, and do we just drop in a slow=release tetra feeder like the big=box
petstore suggested?  Help!
ANSWER: hey.
If the ammonia is at 0, nitrate at less then 10PPM, and all else is good, try doing extra water changes for a bit and see how they are doing. If your tank wasnt cycled before you added the fish, you could be getting high ammonia and need to do the extra water changes.
Hope all goes well!

---------- FOLLOW-UP ----------

QUESTION: Thank you for responding so quickly!  When I change the water I have been
adding the suggested amount of aquarium salt with each change (1
tablespoon).  Is it correct to add salt with each water change?  I also add 5cc
of stress zyme and stress coat.  Should this be done each time also?

Answer
Always use conditioner. Some fish like corys and tetras cant take any salt, but if you have a molly they like salt. The guppy may have not been able to take the salt.
Are you sure the red fish is a platy not a molly? I havent seen any strains of red molly here in Canada, or anywhere really, but Red is the most common strain of Platy.
As for salt, i used to use it, but now i just quit. I havent seen it really help any fish besides mollys. I only use it for hospital tanks.