Mimosa (beautiful beta boy) is being very sluggish. He is usually a dark red color but his color has faded the last few days. Every once in a while he will storm up to the top for air and to say hi but then he will just sink back to the bottom where he will lay. This started when we went away for a week for vacation, but he is usually fine after a few hours after he gets some light but this time he is being very sluggish... it has been 1 week since we have been home. The danios are doing just fine so I dont think the water quality is bad. He leans a little to the side too when he swims, but then at some times he will seem to be doing just fine. Any help?