Just some random info, long time ago my buddy somehow came across a 2" largemouth and put it in a fish tank, lasted almost a year. The line on his side was always brighter for a day or so after he ate, if he hadn't eaten a lot he had no line at all looked just like your picture. Little sucker would eat shiners as big as himself. He wouldn't always eat right away he seemed to not like the chase, just wait and quick strikes at close range.