Sick angel

[DC-FUERTEVENTURA]

Hi the other day all my angels were fine, the next day 1 has refused to eat and staying in top corner of tank, now is bottom to mid depth nose pointing up, showing very little strength, what can I do to try and save this fish as it is one of two silver, black striped red eye Ángel a very pretty fish???!!!
If any one con give me any help fast I would appreciate it really don’t want to lose it.
Had it from about 2cm and now about 5/6cm

 

[foxgirl158]

Water parameters please? (Ammonia, nitrites, nitrates, pH, etc)

 

[DC-FUERTEVENTURA]

Temp 26.8C ammonia 0 nitrite 0 ph 6.5/7 nitrate 0/0.25 kh 5dgh gh 10dgh

 

[DC-FUERTEVENTURA]

All other nine angels fine, this problem happened overnight? Today started nose up.
Also forgot to mention the set up is 300ltr tank 60ltr sump, 800lph external filter and 200lth external running sponges only end to end in sump

 

[foxgirl158]

Hmm… unfortunately, I don’t know a lot about sick fish or angelfish. If it’s not your parameters, I’m not sure I can help, sorry! Best of luck

 

[Colin_T]

pictures and video of the fish?

do a big water change.
gravel clean the substrate.
clean the filter if it hasn't been done in the last 2 weeks.

 

[DC-FUERTEVENTURA]

pictures and video of the fish?

do a big water change.
gravel clean the substrate.
clean the filter if it hasn't been done in the last 2 weeks.

I do a 50% water change on tank volume every nine days with gravel cleaning the tank has been set up 10yrs with no problem until now

 

[DC-FUERTEVENTURA]

Just put the angel in a 60ltr tank on its own after a 15 min salt bath while I set up the 60ltr

 

[DC-FUERTEVENTURA]

Thanks everyone for your help all I can do is wait and see also dimmed the lights down t blue only on the led panel

 

[Colin_T]

pictures and video of the fish?