hook is dead. His death was not unexpected. This morning I found him on the bottom of the fish tank. As mentioned before, he was swaying. The swaying worsened the last days, and it was sad to watch him in this condition.
“Motor incoordination: A general loss of normal coordination of body movements (e.g., swimming on a side, corkscrew swimming); commonly observed as a result of neurotoxicity or other neurological defects (also see Akinesia, ataxia).“
From the zebrafish BEHAVIORAL CATALOG: Kalueff AV, Gebhardt M, Stewart AM, et al. (2013) Towards a comprehensive catalog of zebrafish behavior 1.0 and beyond. Zebrafish 10(1):70–86.