Ok! I'm still needing help.
I performed a 50% water change today (which always includes gravel siphoning) and re-added aquarium salt. I also purchased a heater and am bringing the temperature up to the low 80's as per DogFish's suggestion. Also, to aid in filtration I have put in a more powerful filter (one meant for a 30 gallon - I have a 10) to hopefully aid in keeping the water a better quality (I know goldfish are super messy).
Looking at Sakura (my Ryukin), she has developed a secondary infection of Bacterial Fin Rot. Paul (the moor) is showing signs now too! His underside is obviously tearing a bit. I am treating this with Melafix, a natural tea tree treatment.
Is there hope in these guys recovering or am I just prolonging their suffering? Should I treat with Ick Guard as well as Melafix and Salt? They are still eating when offered food (once a day) so this gives me some hope. I've enclosed a photo of them, because I've noticed Paul's tail is "shedding" the ich and I'm not sure if that's good or bad.
Again, any help in saving these guys is really appreciated!