Dark tail fins on goldfish

[Kristinlynda]

Hi there! I am here because my ex moved out and I am trying to learn how to take care of my four year old goldfish on my own and am utterly clueless. Goldie(my niece named him) is in a ten gallon aquarium with a carbon filter. About a month ago he developed rot. I treated him with Melafix and Pimafix based on a friend’s advice and he recovered quickly but sadly his tail has started to turn dark again and he doesn’t seem to be responding to the medication this time. I have removed everything in his tank and cleaned his rocks and done a water change and removed the carbon filter before starting the second round of treatment. Is there something else I need to be doing for him? I’m so overwhelmed and really want to help him.

[Aiken Drum]

Did you take on the fish, tank etc? Or is it a new set up? New tank, filter etc?

Do you have any idea what your water parameters are?

Bits of your goldfish turning black is a sign of ammonia being too high, which in turn is a sign your tank isnt cycled. In the short term, plenty of water changes are the best thing you can do. For the time being change half the water every day.

Going forward, im conscious that the situation has kind of been forced on you, but a 10g tank isnt going to be big enough for a goldfish. In a suitable environment, goldfish get big and live decades. They are also very messy. The upshot is they need a lot of space, ultimately a tank 3x bigger than you have for just one goldfish. How big is the fish currently? Do you have any idea how old it is? I dont really want to assume how commited you are to caring for this fish in terms of time, money and space.

If you are committed to the care of the fish, then i would get a water test kit. We can then determine if your tank is cycled. API freshwater master test kit is a good one to go for.

I can post some information about the nitrogen cycle if you want to learn about whats going on in the tank. In the meantime here's a link about what to do if you find yourself the owner of a goldfish which contains a lot of useful information.

https://www.aquariumadvice.com/forum...re-377527.html

[Kristinlynda]

Originally Posted by Aiken Drum

Did you take on the fish, tank etc? Or is it a new set up? New tank, filter etc?

Do you have any idea what your water parameters are?

Bits of your goldfish turning black is a sign of ammonia being too high, which in turn is a sign your tank isnt cycled. In the short term, plenty of water changes are the best thing you can do. For the time being change half the water every day.

Going forward, im conscious that the situation has kind of been forced on you, but a 10g tank isnt going to be big enough for a goldfish. In a suitable environment, goldfish get big and live decades. They are also very messy. The upshot is they need a lot of space, ultimately a tank 3x bigger than you have for just one goldfish. How big is the fish currently? Do you have any idea how old it is? I dont really want to assume how commited you are to caring for this fish in terms of time, money and space.

If you are committed to the care of the fish, then i would get a water test kit. We can then determine if your tank is cycled. API freshwater master test kit is a good one to go for.

I can post some information about the nitrogen cycle if you want to learn about whats going on in the tank. In the meantime here's a link about what to do if you find yourself the owner of a goldfish which contains a lot of useful information.

https://www.aquariumadvice.com/forum...re-377527.html

Hi! The tank has been set up since the fish was won at a carnival by niece four years ago. The filter has not changed but I did replace the plants recently because they were slimy. I unfortunately do not know about my water parameters I will order the API test kit today! Goldie is about four years old and about three inches. If he recovers I will look into a more suitable tank for him, I am fully committed to giving all my pets the best life possible I just know nothing so I really appreciate the insight! I never would have guessed that ten gallons was too small for one fish! I will do the daily water changes and test the water. I’m currently caring for four premature kittens so I’m spread a bit thin at the moment but really want to help him.

[Aiken Drum]

At 4 years your goldfish should be about 8 inches, so the small tank has already stunted the fishes growth. This will cause ill health and shortened life expectancy and is probably irreversible. A larger tank will give your fish a better quality of life though.

Its not that a 10g is too small for 1 fish, but it is too small for 1 fish that should grow to 12 inches. 10g is a great size tank for other smaller fish.

If the tanks been running for 4 years, it should be cycled by now. But there could be other factors causing ammonia and its a good idea to know where you are at. For instance the filter may not be big enough.

Here is a link to a page with more information for new fishkeepers if you havent already found it.

https://www.aquariumadvice.com/forum...um-154837.html

[Kristinlynda]

Originally Posted by Aiken Drum

At 4 years your goldfish should be about 8 inches, so the small tank has already stunted the fishes growth. This will cause ill health and shortened life expectancy and is probably irreversible. A larger tank will give your fish a better quality of life though.

Its not that a 10g is too small for 1 fish, but it is too small for 1 fish that should grow to 12 inches. 10g is a great size tank for other smaller fish.

If the tanks been running for 4 years, it should be cycled by now. But there could be other factors causing ammonia and its a good idea to know where you are at. For instance the filter may not be big enough.

Here is a link to a page with more information for new fishkeepers if you havent already found it.

https://www.aquariumadvice.com/forum...um-154837.html

Thank you! I have been reading through it and a neighbor is running to the store for the test kit for me since I can’t leave my kittens right now and don’t want to wait for one to be shipped to me. Hopefully I can get Goldie back on track ASAP and find a appropriate tank to give him the best possible life going forward. It really makes me sad that he is stunted but as my ex was in charge of all decisions up to this point I can only do what’s best going forward. I truly appreciate you taking the time to help my clueless self out!

[Kristinlynda]

I tested the water and the ammonia was at .25 so I did a water change as recommended and WOW! Goldie already looks so much better! Thank you so much! I never would have figured out what was wrong on my own!

[Aiken Drum]

0.25ppm ammonia isnt that bad, but freshening up the water is always a good idea if you are concerned about anything.

[Kristinlynda]

Originally Posted by Aiken Drum

0.25ppm ammonia isnt that bad, but freshening up the water is always a good idea if you are concerned about anything.

Well his dark fins cleared up nearly completely overnight so It must have been bothering him. I think removing the old plants and rocks when I thought they were causing the issue backfired. I definitely have a LOT to learn if I plan to keep this guy healthy 🙃