Lethargic Female Swordtail

[hawil]

I have a 15gal tank with 4 females and 1 male all swordtail except for 1 platy.

One of the female swordtails is not doing great. She is the biggest of them all.
Symptoms:

No external marks/pimples/ulcers/white spots
flashing but not always
always stays at the bottom corner of the tank
dorsal fin, caudal fin, and anal fin is usually clamped
swims time to time but goes back to the bottom corner
she still eats
breathing is faster than usual

I do WC 70% every 2 weeks
The tank is already running for about 4months without issues not until now.

In what I see it is an internal parasite or some sort. What do you guys think?

P.S
I have no water param readings, the test kits are not sold here

 

[hawil]

Anyone?

UPDATE:
I just fed them today, she eats the flakes then spit it back out

 

[saffholly]

Could be a number of things but the fact she's spitting out food is not good. How long have you had her for? has she always been bigger than the others? could she be preganant?

I had a swodtail but had to give her away as she was getting picked on by my male guppies, she would hide a lot and didn't look happy, are any of your fish picking on her? you could treat her for parisites (its worth a try).

Is she pooing ok? could she be bunged up?

 

[hawil]

Could be a number of things but the fact she's spitting out food is not good. How long have you had her for? has she always been bigger than the others? could she be preganant?

I had a swodtail but had to give her away as she was getting picked on by my male guppies, she would hide a lot and didn't look happy, are any of your fish picking on her? you could treat her for parisites (its worth a try).

Is she pooing ok? could she be bunged up?

I've had her for about 4 months now and very healthy not until now. Yes, she was always been bigger than the rest. i'm pretty sure she is not pregnant.

She is not getting picked though but the male sometimes approaches her to poke because they have been partners ever since doing stuff together maybe he misses her or something.

Any kind of internal parasite treatment? Should I treat the whole tank or QT her?

I have not seen her poop now that you mention it.

 

[hawil]

I was also thinking before treating with internal parasite treatment, I would dose the whole tank with stress coat or a related product with aloe vera and see if there is a difference.

 

[hawil]

Just an update. I did a 75% WC and added 10mL (according to instructions) of AZOO Aquaguard. After a few minutes, clamped fins where gone but now she is not eating though she tries to go near the flake but won't eat it. No external marks either.

 

[hawil]

Update:
No clamped fins
Still lethargic
not eating
fast breathing

Now, there is something showing up on her side