I also have 1 GBTA and 1 RBTA, small size. GBTA wasn't and RBTA was bubbly when I bought them. The bubbles were gone once I put them in my tank. Recently, I noticed the GBTA starts to get more bubbly and I am guessing it's started to get used to my tank/water (Bought the GBTA first). They both extend up to catch more light when I turned on my light; just too lazy to move themselves up permanently. As long as they are healthy and happy, I am cool with it.