I have a Figure 8 puffer in his own 10gal tank with lots of cover. SG
- 1.002, slowly raising it up to 1.005. (I just got him two weeks ago, he was in completely fresh water at the LFS
) He was a happy camper the first week, eating and swimming all over the place. The past few days, he's been really lethargic, sitting in a corner all day and he won't come out for food. This morning I found him head down tail up in a plant, heaving. I was just about to put him out of his misery, but when I went to get him, he wasn't there anymore. I found him swimming around as if nothing happened! He still doesn't look great, but he's moving now, it still looks like he's heaving and having a hard time breathing. All water parameters are fine, ammonia-0, nitrite-0, nitrate- <20. His coloring looks a little bit faded but other than that, there's nothing wrong as far as I can tell. Any idea what's going on???