Recently I’ve had a few issues with my aquarium. Black beard algae has started appearing in small clumps (hopefully adding co2 will help with this) and a fish has died (harlequin rasbora). Did a water change straight after the fish died and checked parameters, everything was fine. yesterday I noticed that another fish had the same sort of ‘look’ as the one that recently died. I don’t know what’s wrong with the fish and I’m new to fish keeping. Can someone please help me figure out what’s wrong with my fish before it might be too late. I can’t find anything online and would like to fix the problem. I’m scared there’s some sort of disease going around my tank. The aquarium is 120litres and is heavily planted, I do a 30% water change every 1.5 weeks. If you look at the photos you can see that the fish has some sort of like punctures, or scales falling off on its body and I don’t know what’s caused it, and in real life the fish looks more pale than the others.