Brown Goldfish Turning Pink

I got my 2 goldfish back in April. Since then one of them has died (I believe it was a genetic issue as my other fish was fine and all of the tests I ran on the tank were normal). Now I only have my brown goldfish left. Recently, it has been getting pale in most places except for a few brown splotches. I originally thought it wasn't getting enough sunlight but now its head is turning pale pink. All tests on the tank water came back normal. What is wrong with it?

Can we get a pic of the fish, please.

Hi and welcome to the forum

Besides a picture that Deanasue has asked for, what is the ammonia, nitrite, nitrate and pH of the tank water?

How often do you do water changes and how much do you change?
Do you gravel clean the tank when you do a water change?
Do you dechlorinate the new water before adding it to the tank?

What sort of filter do you have?
How often and how do you clean the filter?

Have you added anything new (fish, plants, wood, etc) to the tank in the 2 weeks before this started?
Do you add plant fertilisers, supplements or anything else to the tank?

How long ago did the fish start becoming pale?
How long ago did the pink area start to appear?

What do you feed the fish and how often do you feed it?

The ammonia and PH were done more recently than the nitrate/nitrite testing. I can do the latter again if you think its an issue with them. Ammonia was good; between 0 and 0.25. PH was a little elevated; however, it was normal for this particular tank. I read somewhere that goldfish like a PH of around 7.4; the recent test (taken today) showed around 7.4-7.8.
I do water changes weekly of around 40-50 percent. I used to do more but I read this could be stressful to the fish. I do clean the gravel as it tends to contain the majority of the waste. I also treat the water (I guess this is dechlorination; sorry this is my first time owning fish) before putting it in.
I have no idea about the filter; there are these thick sheet-like things I put in the filter and I change these whenever they get dirty.
As for recent changes, my other fish died around a month ago and I changed the airstone because the other one was growing algae. I also changed the filter a few weeks back. *Small note about the airstone, the tubing is and has been growing pinky-orange stuff on the plastic tubing. I clean it off every week, but I can find absolutely no information about what it is.
I am kind of ashamed to admit how synthetic my tank is as well. As I said, it is my first time owning fish so I have no living plants (I am really hoping to do this with another tank in the future because I don't want to stress out this fish anymore).
The fish started seeming paler a week or two ago, but it was only really visible within this last week. The pinkness is around 2-3 days old.
The food is another thing I'm not too proud of, I was recommended to buy flakes and listened (I later learned this could case nutrition and air issues), but I have been hesitant to change this and mess up this fish's routine. My fish gets fed a small amount twice a day and has been getting this since the beginning. I also supplement half a pea and some lettuce once a week to add diversity and nutrition to its diet. (This only started about a month ago).

It's a good idea to test the ammonia, nitrite, nitrate and pH any time a fish looks sick. That way you can rule our water quality as a possible cause of the ailment.

Goldfish and Koi carp do prefer the water to have a pH above 7.0, so 7.4-7.8 is fine.

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Dechlorinating the tap water simply means adding a liquid or powder to neutralise chlorine or chloramine in the water. There are lots of different brands available and a bottle of dechlorinator should have come with the tank when you got it.

You should dechlorinate any new water before adding it to the aquarium so no chlorine or chloramine enters the aquarium and potentially harms the fish.

If you are unsure about whether you have any, just post a picture or put the names of the items you have here and we can go through them and tell you what they do.

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You can change more than 50% of the tank water at any one time and I use to do 75-90% water changes on my tanks. The main thing is to remove any chlorine/ chloramine from the new water before it goes into the tank. As long as the new water is free of chlorine/ chloramine, you can change 90% every day and it won't affect the filter bacteria or the fish.

50-75% water changes every week are fine.

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Maramb said:

I have no idea about the filter; there are these thick sheet-like things I put in the filter and I change these whenever they get dirty.

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If you can post pictures of the filter and pads, etc, we can tell you how to clean and maintain the filter.

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There's no need to change airstones unless they block up and no more air is coming out of them. If you do replace them, look for the plastic multi-coloured airstones. They can be taken apart, cleaned and put back together. Some also have a small lead weight in the bottom section, which helps keep the airstone at the bottom of the tank where it belongs.

If you post a picture of the orange stuff on the airline I will have a look at it.

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Goldfish love plant matter and should get some each day. You can use peas, spinach, broccoli, pumpkin, squash or cucumber. Just make sure it is free of chemicals and safe for human consumption. You can feed the fish flake food in the morning and some veges in the evening or vice versa. If it doesn't like them raw, try blanching them (soaking in hot water for a short time) to soften them up.

You can get a floating plant called Duckweed from most pet shops. It is normally quite easy to grow on the surface of the water and the fish will eat that too. I use to grow Duckweed outside in ponds and bring some in each week to put in the tanks. You probably won't need to do that with one fish but you can do it and that will give you a reserve if the fish eats all the plant in the tank.

Some fish take in air when eating food from the surface. The air works its way through the fish's digestive tract (stomach and intestine) and eventually gets expelled out the back end (yes fish do fart). If the fish has air in its intestine, it might have trouble swimming down and staying down. Lots of air in the fish can cause it to float straight back up to the surface.

Feeding the fish a varied diet (not just dry floating foods like flakes) will normally prevent the fish having buoyancy problems due to air in the intestine.

You can buy frozen brineshrimp, prawn, fish and other foods from most pet shops, and goldfish will eat these foods too. Marine mix or Marine green are good options and consist of prawn, fish and squid blended up and frozen into little blocks. Marine Green is the same as Marine Mix but it also contains algae or spinach and is a better choice for goldfish. You can feed frozen (but defrosted) foods 3 or 4 times a week. Just remove any uneaten food after feeding.

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Regarding the fish's colouration, my guess is the fish is losing its juvenile bronze colour and is starting to show off its final colouration.

All baby goldfish are bronze when young. After a few months they will either stay bronze or change colour and might become red, orange, yellow, white or black, or even a combination of these colours. Your fish appears to be pale yellow and might get a bit of white on the side behind the head.

The pink patch on top of the head (just behind the eyes), is the fish's brain. Fish usually have less pigment around the head and face and if the fish has very pale skin, you can sometimes see the blood flowing through parts of the body and in this case, the pink brain is partially visible under the skin.

If the pink become more pronounce throughout the head and face, that can indicate a water quality problem or an infection in the head. The best way to prevent infections in fish is to do big regular water changes, gravel clean the substrate and maintain the filter.

I agree with everything Colin has said except the spot on head. It looks raw to me. What is your ammonia level and the size of your tank? I would do daily water changes of 70% daily for the next 2 weeks and see if that helps. If not, you may need to get some API Furan-2 to treat bacterial infection. I am a Goldie lover myself. You can buy Repashy Solid Gold gel food which is a good alternative to fresh veggies every day. I feed my peas on Sunday and then the gel food each night. I also feed pelleted god in the morning. @Colin_T, can you take a closer look again at head? It appears to be raw to me.

post a few more pics of the fish from different angles.

Colin, thank you so much for all of the suggestions and information. I will get back to you with pictures of the airline and filter. Also, I use a water conditioner which helps eliminate chlorine.
Deanasue, the ammonia level, taken at the time the fish started to become pale and pink was at 0-0.25. I have a 5-gallon tank. Thank you as well for the suggestions. Here are a couple more pictures of the fish:

The rusty stuff on the airline is some form of algae or other organism - I see my algae eaters consume it occasionally - It just wipes off

If the fish is still eating well and the water quality is good (no ammonia or nitrite and the nitrate is less than 20ppm), I am staying with the brain

If you are really concerned then add some salt for a couple of weeks and see if it helps.

You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 4 heaped tablespoons per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate will affect some plants. The lower dose rate will not affect plants.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

View attachment 94360 That tank was s way too small for a comet goldfish, I’m afraid. He will grow to be well over a foot long. This mine. He is now in my pond and is about a foot long.

Jan C.: that's good to know thanks!
Colin: Alright thank you, I'll look into the salt.
Deanasue: Oh my goodness, I had no idea it would grow to be that big; it was one of the smallest goldfish I had seen when I got it.

Maramb said:

Jan C.: that's good to know thanks!
Colin: Alright thank you, I'll look into the salt.
Deanasue: Oh my goodness, I had no idea it would grow to be that big; it was one of the smallest goldfish I had seen when I got it.

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Maramb said:

Jan C.: that's good to know thanks!
Colin: Alright thank you, I'll look into the salt.
Deanasue: Oh my goodness, I had no idea it would grow to be that big; it was one of the smallest goldfish I had seen when I got it.

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I learned the hard way too. That’s why I now have a pond. The fancy goldfish only grow to about 6”. Some of mine are only about 4”. That’s the fantail ones.

Does my goldfish need a companion?

Yes! They are companion fish and bond with others. Since you already have a single tailed I would suggest sticking with that. They swim faster than the fancy ones and will get all the food. If you live in the U.S., Petco has their Dollar a Gallon sale on right now up to 20 gallons. I would upgrade before getting the other fish. I have all kinds of fish but goldfish are my absolute favorite! They’re so smart and lovable. I called them my
“Water puppies”.