Whats Wrong With My Fish?

[squish]

Ok, so i had two angel fish, one has already died and the other one...well i think its on its last legs (or fins as the case may be!)

They are literally standing bolt upright balancing on their tales struggling to breath! Anyone have any ideas as to whats wrong with them/ what i could do?

 

[shang hi]

need more info, fill this in

Tank size:
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp:

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Volume and Frequency of water changes:

Chemical Additives or Media in your tank:

Tank inhabitants:

Recent additions to your tank (living or decoration):

Exposure to chemicals:

Digital photo (include if possible):

 

[shang hi]

okay welll from no information i say it could be swimblader problems but its uncommon for two or multiple fish to have it at the same time.
are they bloated and/or is their anus red, internal paracited can cause this but more info is nessasary!

 

[WILDER]

I agree if water quality is spot on, I would look into internal parasites.
Signs are
Being lethagic.
Being pale.
Spitting food out.
Being bloated.
Being thin.
Anus enlarged or red and inflamed.
Bent spines.
Long stringy white poo.
Not going to the toilet at all.
Worms prutruding from the anus.