Here's the update: good news, bad news, and then good news again.

The GOOD NEWS is that after I revived him (yesterday afternoon), he looked perfectly fine. I mean, PERFECT. He was acting social around other fish.......he was swimming back and forth across the tank, etc.

The only "strange" (?) thing is that occasionally, he would skim the top surface of the water, but only along the EDGE. It's almost like he was trying to find food or something which would be floating along the edge of the tank.......but when I put food there, he wasn't interested. I thought maybe he was trying to eat bubbles (made from the turbulent water), or possibly he was trying to nibble some kind of "film" or something on the sides of the tank. If I tried to approach him, he'd quickly swim away, so he was cognizant and responsive as I would expect.

The only other time I have heard of fish hanging near the top of the water has to do with oxygen deprivation, or bladder issues.....neither of which I believe we're dealing with here. The tank has a LOT of aeration, and I have my fish on a pea diet every few days to change up the diet (normally just koi pellets that I pre-soak in water). So I can't explain why I noticed him skimming the top......but then he would go back down to the bottom and swim around there as well. In other words, he wasn't ALWAYS on the top. In fact, it almost looked playful when he was on the top, swimming around the perimeter of the tank (but not flashing or anything that would scream PROBLEM).

So that was the good news (the fact that he revived yesterday and was acting normal all the way until I went to bed around 10:00pm at night).

Now for the BAD NEWS. I awoke this morning, about to respond to this post, when I thought, "Let me go check on him." Sure enough, I go out there, and he's floating "dead" again in the middle of the tank. By middle, I mean not on the bottom, not on the top.......just floating with the current, stiff as a board, with fins pointed straight out horizontally.

So I tried my thing again. I reached my hand in the water (cold....temps around high 50's F this morning, so I'm sure it was low 50's in the middle of the night).

I held him in my hand, did a couple of gentle squeezes, and then his mouth GAPED WIDE OPEN. A couple more times, and it would close....then open. I began to actually feel like a pulse in my hand, which was him breathing in and out again.

I thought, "CRAP! I should have filmed this for you guys"......so I put him back and he stayed upright while I got the camera. So here is the quick video I got. He's already revived, but he allowed me to catch him EASILY. I give you a close up of what he looks like, just in case you see anything out of the ordinary (because I can't!). Then I let him go and he swam back to the bottom where he is alive again:

[youtube:2gc7wpi8]http://www.youtube.com/watch?v=WdzIIh6qR1U[/youtube:2gc7wpi8]

So that's the final good news, if you can call it that. He's swimming around, and no longer dead.....but the fact that this happened twice to the same fish, with no visible signs of illness, and no behavioral signs (except for the occasional hanging on the surface of the water along the edge, as if looking for something).

I may think the temperature is a factor, but when this happened yesterday, it wasn't THAT cold and happened in the middle of the day. So I'm really perplexed about this one. I just checked on him right now and he's swimming around with the other fish on the bottom of the tank, hanging with their little group. In fact, he might be the more active fish of the bunch, checking in on the other fish and just swimming around actively.

I look forward to your thoughts on this!