Guppy developing bent spine

[BlackAndBlue]

Hi!
So one of my female guppies developed a little s formed spine, today is the second day I have noticed it.

She also seems to have a few black/darker spots on her mouth but that could be just a coloration I have not noticed up till now.
Fish TB or the black spot disease were my first search results but I really can't tell if it is one of these. Could it just be bad genetics or should I seperat her to be sure nothing spreads to the other fish(if it hasn't spread already)? I just don't want to cause unnecessary stress for her. There wasn't any change in terms of her behavior, but currently I am treating them with medecine (for internal worms) and I add salt every water change. I do water changes every three days, about 40-50 litre (because I had problems with No2 a few weeks back) and use declorinator before adding the fresh water.

Wafer parameters:
No2: <0,01
No3: 1
Nh4: <0,05
Ph: 7,5
Tank size: 160 litre
Inhabitants: 2 corydoras, 1 dwarf gourami, 4 audlt mollies, 3 guppies, ~20 endlers, a few molly/guppy/endler fry
I feed all of them twice a day, sometimes with tetra flakes, sometimes with dried, red mosquito larves (also from tetra) and jbl food pellets.

 

[mrsjoannh13]

If you have .05 ppm ammonia that is too high. Nitrite should be 0 as well. Was your tank cycled before you added fish or are you doing a fish-in cycle?

 

[BlackAndBlue]

If you have .05 ppm ammonia that is too high. Nitrite should be 0 as well. Was your tank cycled before you added fish or are you doing a fish-in cycle?

Nh4 shows <0,05 (less than 0,05 since there isn't a 0 on my water test kid. Same with No2.

My tank is cycled and I have had these fish for 6 months in the tank. Before that the tank had a fish less cycle for about 1,5 months. So both parameters are 0, my test just shows it as < 0,05/0,01

 

[Fishiemang]

That is either bad genetics, or ammonia poisoning. Since it has sudden.onset, I would suspect the latter issue.

Your feeding schedule is a bit much as well. Cut that feeding down to once a.day for a.while. See if conditions.don't improve. Unfortunately, every time I have seen that, the fish ultimately dies.

 

[BlackAndBlue]

That is either bad genetics, or ammonia poisoning. Since it has sudden.onset, I would suspect the latter issue.

Your feeding schedule is a bit much as well. Cut that feeding down to once a.day for a.while. See if conditions.don't improve. Unfortunately, every time I have seen that, the fish ultimately dies.

I will cut down the feeding but every feeding is just really small (they need ~20-30 seconds to finish it). But I nevertheless will. And it could be ammonia poisoning but ammonia can't be any lower according to my water test kid... That confuses me a little... (but it I have the chance to I will buy another nh4 test kid, maybe that also shows 0)
But it's sad that I can't do anything for her... I will just monitore her the next few days and look if it gets worse