Platy With Bent Back

[FishLover4+1]

I looked in my fish tank today and saw one of my variatus platys with her face on the gravel and a bent back. She has a few scales sticking out near the bend but I think that it is the bend not dropsy, she literally looks like someone snapped her spine. im in the uk so all shops closed but i have some internal bacteria treatment, some external bacteria and fungi and some aquarium salt.
Tank size:90l (it isnt quite full)
pH:dont have test kit
ammonia:"
nitrite:"
nitrate:"
kH:"
gH:"
tank temp: variatus platys are temoperate so don't need heated water so i dont have a thermometer

Fish Symptoms (include full description including lesion, color, location, fish behavior): balanced on face at bottom of tank, back bent, scales stick out slightly around bend, ragged fins, opening gills really wide and flapping fins around all other fish fine

Volume and Frequency of water changes: for the last 2 weeks 25-30% a week, before that it was 25-30% every 2 weeks

Chemical Additives or Media in your tank: anti-hair algae treatment

Tank inhabitants: about 8 variatus platys, 2 loaches possibly hillstream, hundreds of snails that were accidently / on purpose introduced

Recent additions to your tank (living or decoration): just the snails but that was before christmas
Exposure to chemicals: anti-hair algae, i have changed tap water treatment to love fish tap safe but its been that for a few weeks

Digital photo (include if possible):  it wont let me put on a photo

 

[bluesword23516]

How old is the fish? How long have you had her?

 

[dopieopie]

I have experienced this with a couple older platies. When I noticed it, it was a rapid decline. My water readings at the time were normal, and no other fish ever got sick.

Has your fish also become thin?

Was it a sudden onset?

 

[FishLover4+1]

I have experienced this with a couple older platies. When I noticed it, it was a rapid decline. My water readings at the time were normal, and no other fish ever got sick.

Has your fish also become thin?

Was it a sudden onset?

She seems normal width and i just saw her like that yesterday. the only thing i can think of is that shes broken it somehow. she doesnt move past the bend (which is sideways not upwards). shes about 17 months old and one of my first fry (ive stopped breeding now)

 

[bluesword23516]

there is that possibility. I recently had a fry that hurt her back, her tail was crooked for a while, about 2 weeks but she is fine now.  Maybe she will recover???