Correct goldfish ailment diagnosis.

HominumAnimus

Hello, I am trying to correctly diagnose the issue with my three comet goldfish and I would greatly appreciate any help from experienced fish keepers.

About the aquarium:
They live in a 120L Juwel tank with 10kg of sand as a substrate (which was thoroughly washed before adding it to the tank). There's a 160L Fluval Filter in the tank and one elodea plant. The plant is surrounded by shungite crystal chips (it is scientifically proven to benefit and purify water and is safe for an aquarium). I perform 20% water changes once a week.
The tank has been cycled and I use "JBL brand Biotopol R" water conditioner for goldfish to convert tap water to healthy water. They are fed once a day, alternating between various brand fish flakes, fish pellets that sink to the bottom, as well as peas. Once a week they fast for a day.

About the problem:
Since about the 30th of June each of the fish have been periodically flashing and darting in the tank, while also sometimes rubbing their bodies against the substrate and corners of tank. This behavior so far has been relatively rare - seen about twice a day, from each fish. There have been no visible parasites on the bodies of the fish and behavior seems normal otherwise (including feeding, excretions, swimming and alertness).
Today though I noticed that one fish has a red patch surrounding the very base of the left front fin. It looks as if it is bloody, though fin is functioning as normal.

Possible causes:
Usually would think this was caused by injury, but the fish have been together for more than a year and there is no behavior issues between them and no hazards present in the tank. My suspicions are with parasites as on the 25th of June I purchased a black moor goldfish and after keeping it in a small tank I introduced it to the main tank on the 27th of June. Now I realize it must have been too early and I should have kept it in quarantine of the small tank for 2 weeks. In any case, the moor died on the 29th of June and it was lethargic for the two days prior to its death in the main tank (though was fine for the 2 days before that in small tank). Investigating it after its death I noticed that one of its eyes was much larger than the other, almost appearing to pop out. And it had a small white grain, resembling salt or sugar, on its left side of the body.

Please advise me on what course of action to take as I wouldn't like to see my goldfish suffer. They have all been very healthy up to this point. Should I isolate the one fish with the bloody spot at base of fin and treat with salts for possible parasites? Since there is no other symptoms other than them sometimes darting and flashing (which could also be a water quality issue) I am hesitant to use strong store bought medication as that can be even more hazardous to them, though I have purchased an ich treatment as I suspect that's what killed the moor.

May thanks for any suggestions!

Silverfish

Test for ammonia / nitrate and nitrite levels

Darting and rubbing can be the signs of ammonia burn, amongst other things, and with your tank being very overstocked (sorry) you may have had an ammonia spike due to the increased bioload of a new fish.

Don't add ich treatment until you are 100% absolutely without a doubt sure it's ich, as the treatments for it are fairly tough on the fish.

Berserker

In agreement with Silverfish, I would test for nitrate, nitrite and ammonia levels. A 120L tank is far too small for one goldfish, let alone three. I would start to look for a new home for those fish or they are going to continue to suffer.

glued

Berserker wrote: »

In agreement with Silverfish, I would test for nitrate, nitrite and ammonia levels. A 120L tank is far too small for one goldfish, let alone three. I would start to look for a new home for those fish or they are going to continue to suffer.

A 120L tank is more than enough for most goldfish species. I see people constantly peddle this myth that Golfish need over 100L of water to survive. Goldfish require anywhere between 50L-75L but it depends on what is in your tank and can survive as long in smaller set ups as long as the conditions are good. Live plants, good filter, temperature, water nutrients, frequency of water change, substrate and how clean you can keep the tank are far more important than the size of the tank.

You can keep 3 goldfish in a 120L tank but it requires a lot more work.

kylith

glued wrote: »

A 120L tank is more than enough for most goldfish species. I see people constantly peddle this myth that Golfish need over 100L of water to survive. Goldfish require anywhere between 50L-75L but it depends on what is in your tank and can survive as long in smaller set ups as long as the conditions are good. Live plants, good filter, temperature, water nutrients, frequency of water change, substrate and how clean you can keep the tank are far more important than the size of the tank.

You can keep 3 goldfish in a 120L tank but it requires a lot more work.

Sure, just like you can keep a dog in a wardrobe. It fits in there so it must be grand.

You cannot keep an adult goldfish in anything smaller than a 120L tank. I've had one in a tank that size and it could barely turn around. Goldfish grow to around 12". Here he is; looks ok from the front, was the exact width of the tank.

Silverfish

glued wrote: »

A 120L tank is more than enough for most goldfish species. I see people constantly peddle this myth that Golfish need over 100L of water to survive. Goldfish require anywhere between 50L-75L but it depends on what is in your tank and can survive as long in smaller set ups as long as the conditions are good. Live plants, good filter, temperature, water nutrients, frequency of water change, substrate and how clean you can keep the tank are far more important than the size of the tank.

You can keep 3 goldfish in a 120L tank but it requires a lot more work.

I have an oranda, they're one of the smaller goldfish breeds.
This is his ass.



He won't physically fit into a 50L tank, especially if there's more than one fish.

Berserker

Silverfish wrote: »

I have an oranda, they're one of the smaller goldfish breeds.
This is his ass.

Lovely fish. What size tank or pond do you keep him in?

glued

kylith wrote: »

Sure, just like you can keep a dog in a wardrobe. It fits in there so it must be grand.

You cannot keep an adult goldfish in anything smaller than a 120L tank. I've had one in a tank that size and it could barely turn around. Goldfish grow to around 12". Here he is; looks ok from the front, was the exact width of the tank.

I'm not talking about keeping 3 12" goldfish in a small tank. The bigger and older goldfish wouldn't be compatible in a small tank as they release worse waste the older they get. You can keep three juvenile goldfish in a smallish tank with the correct maintenance. I was just emphasising the point that correct water management is the most important aspect of keeping goldfish.

Silverfish

Berserker wrote: »

Lovely fish. What size tank or pond do you keep him in?

He's in a 350L juwel tank, with an internal filter and an eheim 350e external filter.
Fancies don't do so well in ponds due to the temperature fluctuations.

Goldfish do most of their growing in the first year of their life, so that's when it's crucial for them to have as large a tank as possible from the very beginning.