then all the fish die... and then your plants and BB in the filters loose their food source which in tern kills them...
since you have plants in the tank I would recommend treating with the 1 tbs per 5 gals of salt but if you dont want to treat with salt just follow the directions on the bottle of medicine, is isnt that bad but it does need to be treated even just raising the temp to 85*F or higher 86-87 being better will help...