Okay here it goes.
I have had a 25 gallon freshwater aquarium setup that I have had for around 7 years now.
One of my fantail goldfish has been having recurring septicemia showing in his rear fins/tail. It will appear out of nowhere and within a few hours of me noticing, parts of his fin/tail at his rear start to fall off and it becomes super red in colour with white patches. When this happens he still swims normal and eats fine. The only real symptoms are the bloody ragged tail falling apart. My other black moor and pleco never get sick. This happens to him every month for the past year/year and a half. He is not being attacked by anything in the tank. Water quality is perfect and I have been keeping some salt in the aquarium to help. I have tried Sulfa drugs/tetracycline/minocycline/ nitrofurazone and kanamycin. Every time I have treated, the fish has responded to the treatment and within a few days everything looks good, and after the treatment he will remain healthy for a few weeks. Every time I have used antibiotics I have used proper dosing and proper duration as listed on the packaging, and usually go over the suggest time frame of treatment by a day to be sure. This is now the 14th time he is showing symptoms from this. I do not know what to do anymore. I cant afford to treat this as a chronic incurable illness. I hope someone can help me out there.
It is stocked with 2 fantail goldfish (One gold, one a black moor) and a pleco.
The goldfish are roughly 7-8 years old and the pleco is around 6 years.
They have been kept in the same tank for this entire period.
I perform regular water changes (25%) every 1-2 weeks and use seachem prime.
Lighting is by c5 bulbs. No direct sunlight.
There are a few plants in the aquarium(live) that are doing great.
I feed once a day and all food is consumed within 1-3 minutes.
Water is always crystal clear.
Have tons of aeration by a power-head and bubble disk.
There is a heater in the tank to maintain water temp.
There is good water movement but not too much so they are blown all over the place.
Here is the current tank stats:
AMMONIA - 0
NITRITE - 0~
NITRATE - Very low
FOOD: New life Thera A + with garlic
Filter Media: Canister/ Fluval 205/ Chemical: Carbon/Purigen with biomax
Any help would be much appreciated as I am now considering euthanasia.