that is a very unhappy plant and you have more than one issue
what nutrients are you using , how often are you feeding , what is the Ph of your water ,and , are they in soil?....
when I see plants in this condition , I stop feeding it , they only get water that has a Ph between 5.4 and no higher than 6.0 , I do this for about a week and then gradually start adding nutrients again , I usually start with a little cal-mag....
obviously one needs to react a lot sooner , as soon as I spot a problem , BAM! ..get on it
when a grower waits to long and a lot of damage is done , it is more difficult to bring the plant out of the death spiral and sometimes it’s just to late....
live and learn eh