If ur nitrates are now 40 after a wc then they were prlly 50-70ppm before, so the nitrates could have affected him more then the others, especially since now hes fine.
Keep the nitrates down with weekly 50% wc and they will also grow faster and healthier!!!
#1 S. Vettel
Oh ya, good catch, must have been high. I say do another 20-40% water change.
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