Hi, I'm glad to be part of this community as I some times feel hopelessly lost when things happen in my 50 gallon tropical tank (and other tanks). I have one large angel fish that lost his top fin when the heater burned it. It has since re grown and now he is majestic. King of the tank. I also have 9 diamond tetra's, 2 albino catfish, one large algae eater who is very shy and likes to hide in the fake log. In a 10 gallon tank I have 4 glow fish. In a 20 gallon tank I have three gold fish who usually live outside in a fish pond but are spending the winter indoors.
One of my diamond tetras has a large (1.5-2mm) raised black spot on it. Would anyone know what that is and how to treat it?