Hi Jade.
Are the "black spots" you mentioned similar to those in the following threads:
https://www.myfishforum.com/thread2624.html
https://www.myfishforum.com/thread2873.html
Photos of your fish would be good. Also, info/data on tanks size & setup, water parameters, history (if any), tanks mates, and any other info would help.
Rgds,
RazorBlade
P.S. Try posting in the Fish Health & Diseases section - you might get more responses there.