Sorry for the late reply, I decided to update only when the situation changed.
I released the atlantic sturgeon saturday evening, it's swimming around again as if nothing ever happened.
I'll make a summary here of the steps I took.
2nd of february (around midnight): Noticed it was having trouble staying upright near the edge of the pond, thinking another sturgeon knocked it sideways + freezing or near freezing temperatures cause all my sturgeon to become slow and sluggish so I figured that could have been a factor in it rolling to its side temporarily. I righted it and it went down deep in the pond. Didnt see it after that.
3rd of february: The next morning at around 11am I found it floating bent near the edge of the point, looked as if it could be dead. It was alive but obviously there was a serious problem. I called Jacobs who advised me to check for air locked up in the fish and to try and press that out. Tried this a couple of times over the course of the day while keeping it in the main pond as he had advised me to do so.
The situation did not improve, it didn't seem to blow out much (if any) air.
(Before calling him I had already set up a seperate small pool in the garage to put it in if needed.)
4th of february: Found the fish bent on the bottom of the pond with it's side floating upwards. Called Jacobs again who advised me to leave it alone for a day and check if the situation would change.
5th of february: Found the fish in the same way as the day before, bent on the bottom of the pond. I figured this would only harm the fish if it would remain bent like this for days at a time so I called Jacobs once more and he agreed that I should take it out and put it in the pool. Also bought an extra air pump.
Got the sturgeon out and put it in the pool.
Filled it with approx 50% pond water and 50% tap water.
I kept the water level low so it wouldn't roll over easily, however it bent so severely that it still couldn't remain upright so I had to come up with something.
I used four bricks I had laying around, put two of them end to end and rolled them up in a towel.
I did this twice so I had two heavy soft barriers that would keep the sturgeon in place in an upright position, leaving it no room to roll over.
Video:
http://www.youtube.com/watch?v=UVlYWN_G ... e=youtu.be
As you can see it doesn't do anything at this point except for breathing. Removing those barriers would result in the fish rolling to its side immediately.
Over the course of the next few days I would put it in the 'sturgeon containment system
' at night so it wouldn't roll over and bend again. During the day I would let it swim and leave it out on its own for increased periods of time. The last two days in the pool i took the bricks + towels out and let it swim on it's own. It didn't roll over once.
This is a video before I released it back into the pond on saturday (8th of february):
http://www.youtube.com/watch?v=oNQpENLs ... e=youtu.be
I'm amazed how this fish looks almost dead one day, and looks fine a couple of days later.
I don't think air locked in the abdomen was the problem, since I wasn't really able to get it to blow air out. I suspect this fish is just sensitive to a swim bladder infection, or something similar, that seems to return randomly.
As similar problems seem to be happening with other people's sturgeon as well, I think it may be a good idea to perhaps create a 'how to handle a sick sturgeon' topic and sticky it. If the mods agree I'll create one and write up an OP containing known problems with sturgeon, and how to solve these problems. Anyone who has something to contribute could post it there, that way you could check for signs and solutions there and take proper action immediately.
). I'll elaborate on all of this in my pond topic since that's a better place for it
