Hi, I have a fish emergency. My bristol shunkin is floating upside in the tank, still alive and trying to swim occassionally.
There are 2 fish in tank. Both Bristol Shubunkin. They are about 7 years old give or take. One is large and white. The other is small with a tail deformity.
Floating in various positions, unable to maintain upright when not actively swimming. Lethargy BUT still high appetite. Bottom sitting. Occasionally red streaks in fins. Fin damage (but that's been a long time issue due to the fact-- Spine is deformed, so tail fin hangs down and drags. (A problem that's existed for 5-ish years out of 7 years.)
Tank: Juwel Rio 125 litre + the filter that comes with it. Two pieces of driftwood with two plants attached. Old and established been in tank for about 3 years?
Recent medication in tank: Finrot treatment last week, aquarium salt for trying to help with sickness. Also tried boiled peas (without shells) assuming it was a swim bladder via constipation issue, but peas don't seem to have done anything.
Water changes once a week, 25% of the tank.
Haven't done a recent water test, so I don't have those results.
I originally thought it was swim bladder from not-great diet. Then i thought it might be finrot. And googling around I've seen things suggesting bacterial infection, swim bladder deformation, TURBACULOSIS?!?! because bent spine is a symptom, but could they live SEVEN YEARS with it????, among other things.
The description, the photo, the redness, and the red streaks you describe, all point to impaired water quality as the / a major factor in this instance. A water change of 25% per week may not be enough - you may need to start increasing these to up to 50%, twice weekly.
Water testing of your ammonia, nitrite, nitrates and PH is crucial; let us know the results. As time is of the essence here both for this fish and therefore likely the other fish, then I'd strongly suggest you do a 50% water change now (after doing the test results on the existing water) before the other fish also succumbs. If, for whatever reason, you can't do a water test now, then proceed with the water change anyway - no time to lose on this.
I'd continue with *daily* water changes of 25% for a week at least, and see if this improves the situation. Keep us posted on the situation re this and the other fish (and water test results as you go along).