My little ryukin is chronically unwell. She almost always has clamped fins and looks sick. I’ve given her peas, medicine such as mela and pimafix, and quarantined her. Nothing has done anything. Lately she has just been sitting on the bottom of the tank doing nothing. I thought she was constipated so I tried to give her some peas. I dropped them a little above her, she swam up to try and get them but after a couple seconds ignored them, or if they hit the bottom she’d just ignore them and not forage like my others. What’s wrong? What can I do to help? Would it be the most humane thing to euthanise her? TIA