Some of my experiments require me to look at the rate of regeneration of the caudal fins in adult zebrafish. So I need to image them every 3 days post amputation. Since I need to measure the area of the regenerating fin for every imaging session, it is important that the fish spreads the fin to the same extent during each imaging session. I know that not any method is error free in this case. But no literature explains when the fins get relaxed after anasthetizing them, nor am I able to correlate any of the fish behaviour while in the anaesthetic ( like loss of reflex or response to stimuli), with the relaxation of the caudal fin. Anyone has any suggestion for the same?

Thanks!!