Red spots on my fish

Question
i just noticed that my goldfish had been acting weird (ie hiding behind the rocks) and today i just noticed red rash on the face and tail of one of them.  I had introduced a sucker fish and some snails a few weeks ago.

Answer
Hi Luke,
Thank you for your question. Maybe something came in with the water when you added new fish. However, your symptoms sound like over feeding. Please read and print out this page:
http://steamboats.com/aquarium.html
Write back if you want to discuss further.
Nori