My goldfish has black on him

[fishlover1314]

I came out to my shop to feed my fish and noticed one of them has black on him, I looked it up and it said ammonia poisoning so I tested the tank. The pictures show the results, I’m confused now because the ammonia is 0 or am I reading it wrong.. also I took the fish out of the water to get a better picture that’s why he’s in a vase, he’s happy and swimming around he doesn’t seem sick, all the other fish don’t seem sick either, he’s the only one with black. The temperature of the water is 82 f. I did a water change a week ago, and have added fresh water in every day ish because it’s been evaporating. I did a full clean about a month ago. I’ve had the tank for 4 years I believe, and the fish for the same amount of time. I’ve never had an ammonia issue, I have two live plants one is tiny and has struggled but the other is thriving I think, I have a Pleco in the tank as well, I got him on the 30th of November. I can turn the temp down but I have tropical fish in the tank as well, they’ve lived together for the four years, I did just get the heater about two weeks ago.

 

[Andy Sager]

This is why goldfish are not good mixes with tropical fish. Goldfish do better in cooler water and tropical fish do better in warmer water. There is no happy medium. One side suffers when together. I'd slowly reduce the temperature to 78-79 degrees. Reduce it by no more than 2 degrees in 24 hours. Doing it too quickly can cause Ick.
It's possible the fish got burned on the heater. If you've had the fish for 4 years +/-, it's not likely to be a natural color coming through. That should have happened a couple of years ago. ( Black does not always show through when they are young. It sometimes waits until the fish are a year or 2 old. ) What is alarming however is that the fish is awfully small for being at least 4 years old. How large is the tank you have him in? What are the other fish you have with him? What are you feeding him and the other fish?

 

[fishlover1314]

Thank you for the detailed feedback! I really appreciate the insight into goldfish and tropical fish care. I understand the points about temperature and tank size, but my primary concern is identifying whether the issue is related to ammonia or something else, and how I can best treat it.
Regarding the size and age, I was just estimating—it may not have been exactly four years. The goldfish is in a tank with platies and other goldfish, and the temperature generally ranges from 75 to 82 degrees, though the heater is set closer to 75. Do you think ammonia could be the issue here, or might it be something else?
I’d love your advice specifically on how to move forward with treatment. Thanks again for your help!

 

[fishlover1314]

This is why goldfish are not good mixes with tropical fish. Goldfish do better in cooler water and tropical fish do better in warmer water. There is no happy medium. One side suffers when together. I'd slowly reduce the temperature to 78-79 degrees. Reduce it by no more than 2 degrees in 24 hours. Doing it too quickly can cause Ick.
It's possible the fish got burned on the heater. If you've had the fish for 4 years +/-, it's not likely to be a natural color coming through. That should have happened a couple of years ago. ( Black does not always show through when they are young. It sometimes waits until the fish are a year or 2 old. ) What is alarming however is that the fish is awfully small for being at least 4 years old. How large is the tank you have him in? What are the other fish you have with him? What are you feeding him and the other fish?

• Tank size: The tank is currently 30 gallons. +20 for each other fish.
• Tank mates: The goldfish is housed with platies, other goldfish, and a Pleco.
• Food: I feed a mix of tropical fish food, goldfish food, and pellets for the pleco.
I do water changes once a week and full clean once a month unless it needs it other than that.

 

[fishlover1314]

This is why goldfish are not good mixes with tropical fish. Goldfish do better in cooler water and tropical fish do better in warmer water. There is no happy medium. One side suffers when together. I'd slowly reduce the temperature to 78-79 degrees. Reduce it by no more than 2 degrees in 24 hours. Doing it too quickly can cause Ick.
It's possible the fish got burned on the heater. If you've had the fish for 4 years +/-, it's not likely to be a natural color coming through. That should have happened a couple of years ago. ( Black does not always show through when they are young. It sometimes waits until the fish are a year or 2 old. ) What is alarming however is that the fish is awfully small for being at least 4 years old. How large is the tank you have him in? What are the other fish you have with him? What are you feeding him and the other fish?

I was also told that if goldfish turn black it means they are dying.. what does it look like when a goldfish turns black from age?

 

[Aiken Drum]

• Tank size: The tank is currently 30 gallons. +20 for each other fish.

I dont understand what this means? Is it a 30 gallon aquarium or a 50 gallon aquarium?

• Tank mates: The goldfish is housed with platies, other goldfish, and a Pleco.

How many goldfish? A 30 gallon aquarium can accommodate 1 goldfish on its own. A 50 gallon aquarium 3 goldfish with no other fish. And these aquarium sizes are minimum and won't provide a very good quality of life. Goldfish really need massive aquariums or better still a pond.

As Andy says, that goldfish looks seriously stunted which will in general be effecting it's health. A goldfish should be fully grown at 2 to 3 years. Which would be 10 to 12 inches long for a common goldfish, and around 8 inches for a fancy goldfish. Your photo looks like it's in a cup or a vase, so around 2 or 3 inches? If that's the case your fish did well to get to 4 years old.

For that nitrate test, really give bottle #2 a good shake, like bang it on the counter because that reading just isn't right. If it's still giving such a low reading get a second opinion. Either take a sample to the fish store or try a new test kit.

That pH is very high. Could even be as high as nine. Is it always that high? That can't be healthy.

 

[Andy Sager]

Thank you for the detailed feedback! I really appreciate the insight into goldfish and tropical fish care. I understand the points about temperature and tank size, but my primary concern is identifying whether the issue is related to ammonia or something else, and how I can best treat it.
Regarding the size and age, I was just estimating—it may not have been exactly four years. The goldfish is in a tank with platies and other goldfish, and the temperature generally ranges from 75 to 82 degrees, though the heater is set closer to 75. Do you think ammonia could be the issue here, or might it be something else?
I’d love your advice specifically on how to move forward with treatment. Thanks again for your help!

Adding to what Aiken said, black coloring on a goldfish can be a number of things , not just ammonia burns. No, it doesn't look like you have an ammonia problem but as I said in my response, there is a better chance that the fish got a burn from the heater. When the heater is on and in the heating stage, if a fish was to brush up against it or get pushed into the tube, they can get burned. Based on your test results, that's what is most likely to have happened. There's nothing you need to do or can do for that. Time and good nutrition will heal those wounds. If the black continues to spread, that would be another issue and I'd need a close up pic of the area for a possible better diagnosis. When they get burned, the fin can sometimes look like melting plastic so if your fish's fin begins to look like that, that would confirm a burn.

Regarding the size, even a 3 year old comet ( which is what it looks like you have) should be too large to put into a vase, especially at that angle so your fish is severely stunted.

Regarding the food, Goldfish have a different anatomy than tropical fish have in that they do not have a dedicated stomach to store food for digestion in so they are just basically one long intestine from the mouth the anus. They are constantly digesting food which is why they need to be fed multiple times per day. They also do not process meat protein very well and should be fed a high vegetation diet. If the goldfish are eating more of the tropical fish food than the goldfish food, they are malnourished ( which can lead to stunted growth. ) Just another reason goldfish should not be mixed with tropical fish.

Since your other fish are Platies, I would gradually drop the temp back to 77-78 degrees and leave it there. Platies actually come from water that is not as tropical as other fish so they don't need the higher temp water but they are not goldfish cold tolerant. In fact, Goldfish start getting ready to spawn when there is ice over their heads so they can handle very cold temps while Platies would die under those conditions.

Regarding your maintenance: Goldfish sometime turn black when there is too much of a change in the water quality. What do you mean by a " full cleaning" ?

 

[Aiken Drum]

Adding to what Aiken said, black coloring on a goldfish can be a number of things , not just ammonia burns. No, it doesn't look like you have an ammonia problem but as I said in my response, there is a better chance that the fish got a burn from the heater. When the heater is on and in the heating stage, if a fish was to brush up against it or get pushed into the tube, they can get burned. Based on your test results, that's what is most likely to have happened. There's nothing you need to do or can do for that. Time and good nutrition will heal those wounds. If the black continues to spread, that would be another issue and I'd need a close up pic of the area for a possible better diagnosis. When they get burned, the fin can sometimes look like melting plastic so if your fish's fin begins to look like that, that would confirm a burn.

Regarding the size, even a 3 year old comet ( which is what it looks like you have) should be too large to put into a vase, especially at that angle so your fish is severely stunted.

Regarding the food, Goldfish have a different anatomy than tropical fish have in that they do not have a dedicated stomach to store food for digestion in so they are just basically one long intestine from the mouth the anus. They are constantly digesting food which is why they need to be fed multiple times per day. They also do not process meat protein very well and should be fed a high vegetation diet. If the goldfish are eating more of the tropical fish food than the goldfish food, they are malnourished ( which can lead to stunted growth. ) Just another reason goldfish should not be mixed with tropical fish.

Since your other fish are Platies, I would gradually drop the temp back to 77-78 degrees and leave it there. Platies actually come from water that is not as tropical as other fish so they don't need the higher temp water but they are not goldfish cold tolerant. In fact, Goldfish start getting ready to spawn when there is ice over their heads so they can handle very cold temps while Platies would die under those conditions.

Regarding your maintenance: Goldfish sometime turn black when there is too much of a change in the water quality. What do you mean by a " full cleaning" ?

What about the pH of 9?

 

[Andy Sager]

What about the pH of 9?

Fishlover would need to use the high end pH test to confirm that number. It looks to me as a mid 8 which is what I have here and had in S. Florida where the goldfish had no issues. That said, any drastic change in the pH or water quality can also cause the fish to turn black. This is why a " full cleaning" is disconcerting and needs more of an explanation.
With ammonia burns, the main concern, all the fins should have burn marks which this fish doesn't have and the test results don't show.
There is also the possibility that because this fish is so stunted and malnourished, it may just not be able to handle even minor changes in water quality anymore. Too many unknowns.

 

[fishlover1314]

Fishlover would need to use the high end pH test to confirm that number. It looks to me as a mid 8 which is what I have here and had in S. Florida where the goldfish had no issues. That said, any drastic change in the pH or water quality can also cause the fish to turn black. This is why a " full cleaning" is disconcerting and needs more of an explanation.
With ammonia burns, the main concern, all the fins should have burn marks which this fish doesn't have and the test results don't show.
There is also the possibility that because this fish is so stunted and malnourished, it may just not be able to handle even minor changes in water quality anymore. Too many unknowns.

The fish is 7 inch, I think it’s been about 2 years, and a full clean meaning I suck half to 3/4 the water out and clean all the decor. I use well water. It generally stays at 75 f.

 

[fishlover1314]

Where do you get your goldfish? Mine is from a general pet store. Which means it’s stunted regardless of my tank size. I got it when it was tiny and it has gotten way bigger than it was.

 

[Andy Sager]

Where do you get your goldfish? Mine is from a general pet store. Which means it’s stunted regardless of my tank size. I got it when it was tiny and it has gotten way bigger than it was.

Actually, that's a misnomer. I've had customers bring back feeder comets that didn't get eaten so they raised them to 12" and larger. So just because it's a comet from a feeder tank does not mean it's going to be stunted. It's housing and diet will play a large part in it. I also had to breed Comets for feeders for my 13 pairs of Oscars to eat the fry so I know how large they get to. They are pond fish, not really tank fish.
On another note, that must be some vase if you got a 7" comet into it. I'd love to see it from a full view from the side. My Mother collected different vases so I kinda grew to appreciate them. They are more than just a flower holder.