You should apply counter measures…
Thus far you only destroyed the fishable chest by removing coin contents… so while there was only 1 type of chest in the game far from a variety or surprise on its contents your choice was to be lazy and penalize all players enjoying fishing back then rather than develop anti bot mechanics…
relying on your customers fully is not an acceptable anti bot tactic…
if you want i can give you 3 valid anti bot designs, none which permanently removes it but rather prevents cheap bots from working…