Fish are lazy Urgent reply

Dear(s)

i got a problem that my fish one by one is dead. now see attached pix.these two are now at bottom all the time nothing eating. rare movement. 10 days before sudden fungus attack in my aquarium and i treated it with fishmox (amoxicilin). 5 were dead but 5 are alive (including these two).
now what should i do and y these are lazy ? ( i new and dont have much exp in this field)

What is your current water temperature? Gold fish will often get more lethargic at higher temperatures. If the temp is above 70-72 F try dropping it by 1 or 2 degrees each day until you get to about 66-68 F and see if that helps. You might also try adding a bubble stone to increase the oxygen levels and by all means get your water tested and list your parameters: Ammonia, Nitrite, Nitrate, pH, Alkalinity. After you can let us all know these we can better help you.

i have bubble air stone,
tem is 71-72 f
ph is normal
I have tape water and anti chlorine (4 drops per gallon)
Regular 20 % water change (twice a week)

I would try to drop the temperature in your tank by 1 or 2 degrees each day until you get down to between 65-68 F and see if you see a response from your fish. Is the pH 6.5, 7.0, 7.5? Normal is different to different fish. If you don't have any water testing supplies you can take a water sample to Petco or Petsmart and they will test it for free. Take about 1/2 cup at least. Ask them to tell you what each of the following values are testing at:
Ammonia- should test 0
Nitrite- should test 0
Nitrate- should test between 0-40 if higher, water changes are needed
pH- 7.0-7.5 preferably
Alkalinity- over 80 ppm

If all of these are testing within desired ranges, then there is something else going on that is not related to water quality. It's easier to fix if it's just a water quality issue.

If your alkalinity (or hardness) is under 80 ppm, then you may be experiencing pH swings that would be stressing your fish. You need some hardness to keep your pH stable.

Don't buy any pH up or down or buffering products that aren't a natural buffer because you are more likely to end up with a pH swing that is more stressful than a pH that is too low or too high.

If it's an internal parasite or a fungus you can try salt in the water and garlic juice or ground up canned garlic squeezed small enough for them to eat it.