Goldfish Is Acting Odd

[Khanna]

Size of aquarium/pond - 20 gal
Types of fish - Red Ryukin Goldfish
Number of fish and sizes - 1, about 2 inches
Filtration used and how do you clean it and how often - Internal filter, Once a month
How much in the way of water changes and how often -- 25%, weekly
Do you dechlorinate - Yes
Symptoms of sick fish ie, spots, behaviour, etc - He has white spots above his eyes, and his fins seem frayed. I've been giving him peas for swim bladder due to some lethargy,  but today after a water change he perked up immensely, and that's why I noticed his fins. He floats upside down and seems to have no control of his back fins, and frequently has to swim down because he his belly floats up.
How long has the fish been sick and which medications are your currently using or recently used - Lethargy for about a week, now this. No medicine.
Test results for ammonia, nitrite, nitrate and ph both from the tap and tank -
Tank-
Nitrate- 20
Nitrite-0
pH-8.4
Tap-
Nitrate-0
Nitrite- 0
pH- 7.8
Anything else you need us to know - He was floating on his back today. I was convinced he was dead but he jolted after I prodded him.

 

[goldfinger]

You could use a large temp netting to house him in his current tank, to help him support himself , but thats not going to cure it!
I would watch him after a feed if he does it right after he proberly has constipation so crushing up some small peas for him this might help him to go.
Check the colour of his poo if there is unprocessed food in this poo( darker strings of poo) it usually means that you are over feeding the poor fella!
Ph seems a bit high they do well I think @ 7.4-7.8PH Might need to look at lowering it if you hit 8.4PH from tank seems quite hardwater you have there but leave the water to stand for 24hours before testing it to see if it drops?

 

[This Old Spouse]

What is the ammonia reading?