Health query: Panda cory in a bad way :(

[chloespeaks]

1. Water parameters
a) 74-76 F
b) pH: 7.4
c) GH don't know- don't have tests
d) KH don't know- don't have tests
e) Conductivity or TDS (if GH and KH aren't provided) don't know- don't have tests
f) Ammonia: .25ppm
Nitrate: 0 ppm
Nitrite: 5-10ppm
g) Water change frequency
once a week 30-40%
h) "Routine" water treatments: Prime (chlorine) + Flourish (plant fertilizer)

2. Tank set up
a) Size 17 gallon
b) Substrate: Small gravel
c) Filtration: HOB sized for up to 30 gallon
d) Furnishings: Live plants and wood
e) Other tank mates: total of 11 fish (7 other types of corydora, 1 neon tetra, 2 threadfin tetra)

f) How long has it been set-up?: 3 years

g) Food used and frequency: Hikari wafers for bottom feeding fish, 3 wafers once a day plus a tiny pinch of powdered food for tetras, live food - mostly frozen brine shrimp - half a cube once a week and peas once a week after a fasting day

h) Recent changes : NONE

3. Symptoms / Problem description or history
Late last night, he was bent and floating at top. I turned on the light and he swam away into the plants. I tested a strip for extreme variances in ph, nitrates, etc. and nothing was very bad. ( I have some of those instant strips for quick look). I did an additional test for only Nitrates from the API Master Kit. This morning he is lying behind a plant, still breathing, but very labored.
Eyes seem a little bigger but not overly. Now I see that his fins are a little smaller than usual (fin rot?) and there appears to be blood in the body cavity, no swelling. IS THIS swim bladder infection?

4. Action taken (if any)
Moved into a 2 gallon hospital tank just now.

5. Medications used (if any) / changes in fish observed since treatment began (if any)
None, but am considering a full spectrum anti-biotic (Cipro) - have done this before to my corys when I am suspecting bacterial infection.

[CorySlo]

I would go with cleaning aquarium, changing most of the water and medication against bacterial infection. Dont believe that you will be able to save the sick one.