DId you test your water params to see what the effect was? I thought that when that happens the plants release all the chemicals that they had been filtering.
Welp, did the 3rd 5g (probably 20%, considering my tank is 29g but the rock/sand displaces a lot) waterchange in as many days and my lil fellas all look happy again. Whew! It was the ordeal everyone said it could be.