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Originally Posted by mr_convitbau  Would the black patches be caused by the high level of ammonia in the tank? I heard someone said so. Is that correct? |
Do you have a high level of ammonia in the tank? If so that can cause various problems including discolouration and can kill your fish so needs to be addressed quickly. Start with 50% water changes daily and stop feeding until you have zero levels. Your fish won't starve but ammonia can kill them.