Please please please help!
Ryukin/fantail looks very unwell, all this suddenly onset overnight 2 days ago and is getting worse:
- Showing black - dark red pathes on gill covers
- Few black specks on body and a few black streaks following fins and tail
- Hardly moves (even for food), sometimes breathes fast and occasionally has what I can only describe as strange "palpatations" in her stomach.
- Eats very little
- Sometimes lies face down/up, though she has always suffered from swimbladder problems

I suspect possible ammonia burn, and have changed 50% of the water each day for 2 days but she is getting worse, hardly moving at all now. Just sitting at the bottom and the black patches have grown. Her fins are looking very raggedy but this may be because they have black lines down them and they just aren't moving.

*Whimper*

Ammonia Level ~ unknown
Nitrite Level ~ unknown
Ph Level ~ neutral (6-8 pH paper says 7.0, dunno how accurate this is)
Ph Level out of the Tap ~ unknown
Tank size ~ 20L
How long has it been running? ~ 6 months
What kind of Filtration? ~ none, very small filter sucked up other fish, now afraid of filters
How often do you change the water and how much? ~ usually just under 50% a week
What kind of Water additives or conditioners? ~ Safe Guard - removes chlorine, chloramines, heavy metals, ammonia
Any Medications add to the tank? ~ none
How many fish in the tank and there size? ~ just 1
Add any new fish to the tank? ~ nope
What do you feed your fish? ~ fish flakes
Chloramines Level from the Tap? ~ unknown
(Sorry, I can't provide that much information.)

20 litres is only about 4 or 5 gallons i think and without a filter your fish is im afraid slowly dying from high ammonia and nitrite levels.
for that size tank you need to be doing 100% change every day at least.

if you can, try and get a bigger tank of around 10 gallons with a filter. the black is the healing from the ammonia so it sounds like the fish is in a bad way. do you have anything larger that you could keep her in just now and gently change her over each day. adding a teaspoon of aquarium salt for each gallon will help the breathing.

Alright, cheers. There's nothing I can put her in until tommorow larger than the aquarium and all I have is table salt, which also has E504 and E535 in (magnesium carbonate and sodium ferrocyanide, I don't know if these are poisonous).
The sudden onset of this is also a bit strange, she's been fine for over 6 months until now.
Thankyou again.

dont use table salt, get the aquarium salt.
as the fish grows so the demands on the filter grow, so the bigger she gets the more ammonia she puts out.
are you uk? if so what filter are you using. goldies need 10x filtration and most cannisters give 4x.

is she a common or a fantail type. if shes a common then they need more swimming space for growth so a 20 is needed. fantail types can get along fine in a 10.
hope some of that helps you. good luck

Have you tested your water parameters? The patches sound like ammonia burn. If you don't have test kits, a pet store should be able to test the water for you (have them write down the reading numbers). You should also consider buying test kits (ammonia, nitrite, nitrate, ph).

If you have any ammonia, you'll want to start doing water changes.

Do the water changes and add sea salt. I live in the subarbs, and I found an all natural gormet sea salt at my store, you should find it in your typical grocery store. 1tsp per gallon. And get a bigger tank. Thats way too small. Take pictures of her and call up a fishy specialist. I don't like the black spots. Beging to think if there is a parasite in there. Also, put a little bit of stress coat in the water, she is stressed most definately. Not only from being sick, but because how small the tank is.

Any news on your fishie, Cypherzero?