My one year-old angelfish seems very lethargic today, he seems to be staying in one spot. A rogue plant leaf was just balancing on his head for a full five minutes - that's how still he is. I've also noticed he has blood-red rings around the base of his fins and is only using his left fin. What could be wrong with him?

One of my mollies has today developed the cotton wool fungus and I've treated that. Could this be related?

Could be ammonia poisoning caused by a water quality problem,

http://freshaquarium.about.com/cs/di...oniapoison.htm