My Kissing Gourami Won't Eat Or Do Much Else.

[Prancytime]

I've got a kissing gourami who lives by herself in a 20-gallon tank. For almost two weeks now, she has been perched in a plant near the top of the tank, hardly moving. This is her. Occasionally she's swim to the surface and back down, and if I disturb the plant she's resting in, she'll swim around feebly for a little bit, but that's the only activity I have seen out of her. I don't know that she's eaten anything at all in that time. I'm kind of amazed she's still alive, but I'd like to keep her that way if I can.
 
She seemed perfectly happy before the onset of whatever this is. So far, I've tried feeding her skinned peas and bloodworms, adding aquarium salt, and using API's "General Cure" powder. I can't tell that any of that has done anything, and I don't really know what else to try. I'm pretty fond of this fish, so I'd be very grateful for anything you can suggest.
 
More details:
 
I change about three gallons of her water every week. It's at about 82F.
The tests I have don't give me numbers, but they say the nitrate, nitrite, hardness, and chlorine levels are all normal.
The pH is a little low (~6.2, I think), so I added a handful of small seashells about a week ago to try and bring it up.
 
The fish is about 3 years old, I think, and about 4 inches long. When I asked about this elsewhere, someone mentioned that that's small for her age. (I actually said she was three inches there, because I estimated poorly, but my guess is that the observation still applies.) She had a bunch of tankmates once, but none of them lived more than a few months, so she's been alone for a couple of years now.

 

[Lunar Jetman]

When I click on the link I get a coin?
I think you could easily change more water each week, say 25-30%

It could also be that your fish is a bit lonely. I'd also be worried if you can't get any other fish to survive more than a few months too.

 

[Prancytime]

Oops, thanks for pointing that out. That's a little embarrassing. Here's the picture I meant to link.
 
I'll try stepping up the water change frequency and see if that helps.
 
I haven't added any more fish in part because I've been moving around a lot the last few years, but if you think getting her a friend would help, I'd be open to the idea. Do you think adding a pleco would do it, or should I try to get something more lively?
 
Thanks for responding!

 

[Timberbatch]

What a lovely coin! Haha no worries, everyone makes mistakes
 
So is she not eating at all? You could try algae tablets, Gouramis are quite fond of them I've found. And although Kissing gouramis can get up to 12in. all fish are different and some may not get that size.
 
You can certainly try to get her a companion, something around her size might work.
 
Best of luck, keep us updated please!

 

[Prancytime]

It isn't looking good.
 
She's still not eating anything, and now she's resting in all sorts of uncomfortable-looking positions - on her side on the rocks, or upside-down between tank decorations. A couple times I thought she was dead and got ready to scoop her out of the water, but then she swam away. I don't know what's going on, but I think what she needs now is a miracle.

 

[DreamertK]

Try doing 5g WC's every day and making sure to dechlorinate and match the temps. Doing the WC's just improves the water quality and in many cases helps the fish out. It might be an infection, but I'm no doctor. I'm a little bit concerned about your testing equipment??? NH3 and NO2 should always be 0ppm (the lowest possible reading).