I tried adding a new piece of driftwood to my 55 yesterday, and I must not of soaked it long enough, because it still wont sink yet. So I take out the piece, do a 20% water change and go out. I wake up the next morning to my fish floating at the top of the tank gasping for air. Check my levels , everything looks fine. (I do have the strips though) which are not always accurate. I go to work, and on the way home I buy a airstone. I do already have a fluvial 405 filter going. I come home and my istlanum is on his side barely alive, and the convicts or still struggling at the top. I throw the airstone in, and do another small water change. So far the convicts are swimming around a little more now, and the istlanum is atleast upright in his cave. I will keep everybody updated on the progress.