How long can fish live at 100ppm nitrate?

[FishFriend0]

Hello it’s me again. My friend has come to my house to feed and look at callamanus worms in my fish tank. One was dead and looks to have been for quite a while as it is looks quite decayed. She did a test and saw the test results linked. She added eSHa ndx and will do water change tomorrow, do you think that the fish will be ok in this level of nitrate for 24 hours before she does a 75 per cent water change.

 

[Naughts]

Do the water change now to dilute the ammonia which is the bigger problem. The nitrate is also way too high for comfort.
If the ndx hasn't had time to work, replace the proportionate (75%?) amount and no more. The camallanus worms will probably need repeated treatment, they are known to be persistent.