Swordtail with internal parasites or waisting disease?

[Tripping Willow 91]

Have you tested your water?

Yes

If I did not test my water...

1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

If I do not change my water...

1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

Can someone help me figure out what's wrong with my sword tail, I've had him for 7weeks and he's very skinny. From the day I got him he's not been right swimming around on his own spending a lot of time on the surface, heavy breathing and often excreting white/clear stringy poo. The last couple weeks he's seemed to improve, doesn't hang around at the surface, good breathing but still very skinny and sick looking and still producing the stringy white and clear poop .

He swims about on his own and has never lost his appetite, he's eating all the time but he's obviously very weak and never even bothers with any of the females in the tank.

One of my other swords was acting in a similar way, it had the stringy poop and spent the majority of time up on the surface hiding behind the filter pipes . With this fish the odd behaviour only lasted a day and it never got skinny. It's been 2 weeks now and it's looking in good health and has not exhibited any more signs of I'll health so I'm not sure if this is related to what I'm seeing in the little male

I originally suspected internal parasites and purchased Esha ndx to treat but I've since decided it could be waisting disease and not worms so I've not treated with Esha.

Any ideas on what it could be or what to do. Should I remove the fish, treat the whole tank with the Esha ndx, should I euphanize it? I have 6 other swords and 9 meeki in the tank and would hate to start losing fish

 

[Tripping Willow 91]

My parameters are
pH 7.8
GH 20
KH 10
Ammonia 0
Nitrite 0
Nitrate 10-20
I perform 1 or 2 weekly water changes of 50-70%

This is the other fish that was exhibiting signs of illness for just one day and has looked tip top since. This fish is a large 3" male that looks like a female

 

[Tripping Willow 91]

I decided to treat with the Esha ndx not sure if it was the right call but I think it's fairly easy on the fish so I don't see it causing any problems.

I've read about using Epson salts in similar situations to mine, this will be my next port of call if I don't see any improvement in the coming days.

Anyone have any other suggestions or advice?

 

[Fishguy17_Tigerfish]

Yea I say aquarium salt should do the trick if you catch it right away and do water changes more often