im assuming you mean the white dots, it may be ich. hard to tell though with no information
parameters mainly.. that helps but parameters are most important.
parameters are probably out of wack, whats your water change schedule?
nitrates are probably high. which would stress the fish and cause ich potentially.
nitrates should be below 20. start doing water changes Id say 50% to start. and that ammonia shouldn't be existent. watch that
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