Betta Fish Tumor? May Be Sick?

So my Betta fish Eugene has a large bump on his side. I was thinking that it is either a tumor or he’s constipated. I found white transparent clumps with his pellets in them at the bottom of his tank. I don’t know if he spit them out, or didn’t digest them correctly. If anyone could give me pointers on what’s wrong and how to fix him that would be amazing! I’ve had him for 7 months and he used to build bubble nests constantly. It wasn’t until 2 months ago when he stopped but I wasn’t sure why. I use conditioner in his water and feed him mainly pellets. I used to include flakes in his diet but I cut them out after he stopped building nests cause he didn’t seem interested in them and I thought they may have been part of the reason why he wasn’t feeling so good. I noticed the bump about two weeks ago. Thanks for the help anyone!

He’s in a 5.5 gallon tank and it’s heated on average at 80*F.

 

Can we see a picture from above him? Can you also fill in this template so that we can have more information to help you: https://www.fishlore.com/aquariumfishforum/threads/aquatic-emergency-template.376562/

The uneaten pellets are decomposing and have fungus growing around them. Remove all uneaten food so they don't pollute the water.

 

The fuzz around the food is just the food decomposing. I'de get a turkey baster and remove it so it doesn't foul your water unless there is something else in there to feed on it. As far as the tumor I don't think I can be much help aside from if he is still eating a few pellets and seems active he may be able to live with it but a better betta pro will chime in with more opinions i'm sure. Good luck! He's a beauty!!

 

What is the water volume of the tank? 5.5 gallons
How long has the tank been running? 7 months
Does it have a filter? Yes but I don’t use it since it’s to strong. I have a miss ball in there and I do frequent water changes.
Does it have a heater? Yes.
What is the water temperature? 80*
What is the entire stocking of this tank? Just eugene my Betta. And 1 missed ball.

Maintenance
How often do you change the water? 50% every two weeks. Then once every month and a half I do a 100% water change.
How much of the water do you change? 50%
What do you use to treat your water? Imagitarium betta water conditioner
Do you vacuum the substrate or just the water?
No. When I do a 100% change I wash it really well with water.

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? API testing kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 0ppm
pH: between 7.0 and 7.2

Feeding
How often do you feed your fish? Once or twice a day.
How much do you feed your fish? Two-three pellets in the morning and two to three in the evening. If he’s only being fed once that day it will be four to five pellets in the evening.
What brand of food do you feed your fish? ZooMed micro floating betta pellet food
Do you feed frozen or freeze-dried foods? Sometimes I’ll give him freeze-dried blood worms as a treat. Very rarely though as he doesn’t eat them much.

Illness & Symptoms
How long have you had this fish? Since September of 2018. So almost 11 months. I was wrong before.
How long ago did you first notice these symptoms? Two weeks ago.
In a few words, can you explain the symptoms? Large bump on his side.
Have you started any treatment for the illness? No.
Was your fish physically ill or injured upon purchase? No he wasn’t.
How has its behavior and appearance changed, if at all? He no longer makes bubble nests. He hasn’t made one one in two months. I noticed the large bump on his side two weeks ago.

 

So there are several things I see of concern and I'm going to address them in order from the template. I see that you don't know about the nitrogen cycle and suggest that you research more about it. Basically all tank inhabitants produce ammonia as waste which is toxic, but you have beneficial bacteria to convert it to nitrites then nitrates which are less toxic and can be removed with a simple water change. This is why a filter is needed and essential for all tanks because it houses the beneficial bacteria which keeps your fish from being poisoned to death. If the filter is too strong then look into creating a baffle for it or getting a different one.

It's also ill advised to do a 100% water change as that's very stressful for fish and you'd have to re-acclimate the fish back into the tank so that you don't put them into shock with a temperature or pH difference. So partial water changes should be done instead.

That does look to be an internal tumor on his side. Unfortunately there's no treatment, but they're usually harmless and shouldn't affect him. As bettas get older they usually stop building bubble nests which could be the reason why he stopped.

 

When I checked off I didn’t know about the nitrogen cycle I thought it was an special email chain for this site. I do know about the nitrogen cycle sorry for any confusion.

As for the filter I’ll get on that. He always hides from it and my roommate told me her sister’s fish got his fins torn apart with their filter so I was weary to use it.

The 100% water changes have to be done sometimes as I’m a student and can’t bring my tank home with water in it. I always leave some of his water in a travel container for him to travel in and put that water back in the tank afterwards. I always acclimate him to the water before he’s back in the tank. Thank you for the help and information. Have a happy 4th!