Goldfish has large bulge on his side

  • #1
My goldfish of almost two years has a very large bulge on his right side. This appeared seemingly out of nowhere, he looked perfectly fine yesterday. I've been attempting to self diagnose it, reading through websites, looking for what it might possibly be, but all I have gotten are horror stories. I'm now thinking the worst, is it a tumor? Is it cancer? Is there nothing that can be done to fix him? Please, please help me, it would absolutely break my heart to I lose him

Here is all of my information: (I copied this list from another website, just fyi; let me know if you need any other type of info)

1. I have two fantail goldfish who have been in the family since last February. Both have been extremely healthy, excepting one incident with white dots on their tails about a year ago, but that was treated fairly easily and quickly.

2. How long are they in body length (not including tail) combined? Goliath is about 2 inches long, not including his tail. With tail, about 3 inches long. David is a little less than 1.5 inches long, excluding tail. With his tail, he’s about 2 inches long.

3. What size is their tank, aquarium or pond? They are in a 38 gallon tank.

5. How often do you change out water? What percentage is normally exchanged? I usually do a 25 – 30% water change every Saturday.
Have you just performed a water change? What percentage was exchanged? This past week I was out of town, so they went without a water change for almost two weeks. I did a 30% change on Friday.

6. Do you use water treatment? What type? I use Topfin Water Conditioner every time I perform a water change.

7. Do you have a filtering system? What type? Does it contain charcoal or carbon? Does it contain a disposable cartridge? Describe your maintenance habits with filter or pump. I have an Aqueon QuietFlow filter system installed. The filters contain carbon. It is a disposable cartridge and I replace them every two to three weeks, usually. I replaced it this morning.

8. Does your tank have a graveled bottom? What is the thickness? Do you use a gravel vacuum? The gravel at the bottom of my tank is less than an inch think and I do use a gravel vacuum every time I clean the tank.

9. Is your tank or pond planted? Have you recently added a new plant? I have no live plants.

10. Are you the primary care taker? Accept for occasionally feeding them when I am not here, no one else takes care of or does anything with my fish or the fish tank.

11. What type of fish food do you feed? How often do you feed? I feed them Aqueon Goldfish Granules once every day.

12. Has your tank or pond completed the nitrogen cycle? Yes, I’ve had the tank for about two years. Made sure it cycled before the fish were ever put in it.

13. What are your tank water parameters? (I am using Tetra Easy Strips to test the Hardness, Nitrate, Nitrite, Chlorine, and Alkalinity.)

A. Temperature? My thermometer is broken, but I want to say the temperature of the water is around 70 degrees.
B. pH? 7.6 For the pH, I used API pH Test and Adjuster Kit
C. KH? Between 80 and 120
D. GH? About 150
E. Ammonia? 0
F. Nitrite? Less than 20
G. Nitrate? 0
Are these results before or after water change? I changed the water on Friday so this would be in between water changes.

What are your tap water parameters?
B. pH? 7.6
C. KH? Between 120 and 180
D. GH? About 150
E. Ammonia? 0
F. Nitrite? Between 0 and 0.5
G. Nitrate? Between 0 and 20

15. Where in the world are you located? Do you live close to the sea or by the ocean? I live in New Orleans, Louisiana. So, I am near the Gulf of Mexico and Lake Pontchartrain.

16. Have you recently used chemicals in the area the tank or pond is located? No.

19. Has the main tank or aquarium been relocated recently? No.

20. Has the fish in question been quarantined? No.

21. Is the tank open or enclosed? There is a small gap between the lid and the aquarium, the clear tube that runs to the bubbler does not let it close all the way.

22. Have you recently medicated or salted? No. Although I do have aquarium salt (API Aquarium Salt) that I have been contemplating putting in the tank since I saw him this morning.

23. Describe goldfish behavior or symptoms: Goliath is acting completely normal, he seems very happy, isn’t having any trouble swimming, but he has a massive bulge on his right side. It popped up overnight and I have no idea what could have caused it or how to treat it.

24. Does your fish exhibit any of the following symptoms?

A. Clamped or folded fins? No.
B. Red streaks in tail or red blotches on body? No.
C. Pressed to bottom of tank? No, not really. When I came in I did notice he was resting on the bottom of the tank, however, as soon as he saw me he swam up to the top and has been floating in the middle of the tank since.
D. Lack of appetite? No.
E. Missing scales or frayed fins? No.
F. Fungus or abscesses? No.
E. Swim normally? Yes.
F. Goes to surface frequently; gasping? No.
G. Is the fish swollen? In one area or entire body? He has a bulge on his right side, his left side is perfect.
H. Are the scales raised? In one area or entire body? They are not raised, per say, but on the area of his bulge you can see a little ridge at the bottom of the scales. It is not very noticeable, however.
I. Darting or rubbing against decor or substrate? No.
J. Changing colors? No.
K. Tumors or bumps? Just the bulge on his side, I am praying it’s not a tumor.
L. Bulging eye or bleeding from eye? No.

I am going to attempt to upload pictures of Goliath and, if I'm able, a video of both fish. Thank you so much in advance.
  • #2
Good afternoon and Welcome to Fish Lore!

Sorry to hear that your fish isn't feeling up to par. Sadly, it does sound like it may be a tumor and if this is the case there is really nothing you can do but let Mother Nature run her course.

I lost an elder Bloody Parrot this past year that developed a tumor the size of a baseball. I left her alone until it got to the point she could no longer swim correctly and I let her go.

I do not believe constipation is the issues since you are only seeing swelling on 1 side of the fish and not both.

Best wishes for your fish and hold on for more responses.

May be graphic photos in the link below!

  • Thread Starter
  • #3


  • Thread Starter
  • #4
Thank you for the quick reply, Ken.

That is horrible news. Is there really nothing I can do? Would adding Epsom salt to the tank reduce the swelling at all? Should I put Goliath in a separate tank and attempt to treat him without David being affected?
  • #5
Good morning,

My best advice is to let Mother Nature run her course at this point. I wish I had better news for you. I know it isn't easy.

Let's get some more responses.

  • #6
Goldfish have been carelessly bred, which has resulted in some unfortunate medical problems, a wide variety of them, bent spines, genetic defects, and tumors... it does appear to me like your guy may have a tumor, and to my knowledge, I don't think that's something that can be fixed. My goldfish recently succumb to a genetic defect that only started to develop after he was 2 years old. I'm so sorry you're in this situation. *hugs*

Similar Aquarium Threads

  • Locked
  • Question


Top Bottom