Mysterious Betta Lump

The fish emergency template is located at the bottom of this thread along with photos.
This morning I noticed a large lump on my bettas left side. He has never gotten any type of lump before and I'm beyond panicked. I'm hoping its constipation but I looked at photos of dropsy and I'm scared. He is still very active and interested in me as I view and talk to him.

Tank

What is the water volume of the tank? 5 gallons
How long has the tank been running? I got this 5 gallon in February
Does it have a filter? yes
Does it have a heater? yes
What is the water temperature? 78degrees (f)
What is the entire stocking of this tank? 1 male veiltail betta, 1 ghost shrimp, 1 zebra nerite snail, 1 large fake hide, 1 small fake hide, 1 small moss ball, 5 fake plants, 1 petite anubis, gravel, filter, heater, thermometer

Maintenance
How often do you change the water? every 5 days
How much of the water do you change? 100%
What do you use to treat your water? water conditioner and bacteria starter
Do you vacuum the substrate or just the water? yes I vacuum the gravel

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

Ammonia: 0
Nitrite: 1.0
Nitrate: 20
pH: 6.8

Feeding
How often do you feed your fish? once daily
How much do you feed your fish? typically 5-6 pellets, he hasnt been eating great lately so its been much less
What brand of food do you feed your fish? Omega One betta buffet
Do you feed frozen or freeze-dried foods? sometimes freeze dried bloodworms

Illness & Symptoms
How long have you had this fish? 9 months
How long ago did you first notice these symptoms? lump today, hes been less interested in food for about a week
In a few words, can you explain the symptoms? large lump
Have you started any treatment for the illness? not yet
Was your fish physically ill or injured upon purchase? no
How has its behavior and appearance changed, if at all? hasnt been eating well for about a week, large lump today

 

Could be a tumor. I'm not sure.
I am worried about the nitrite. You shouldn't have any nitrites. Do you usually have nitrites or did you catch the tank at a bad time?
Also, if you've had the tank cycled for all the 9 months you've had him since February, I see no reason to add bacteria starter in at every water change. You should have bacteria already established. Unless you're doing so because of the nitrites? How do you clean your filter?

You can try feeding peas or greenbeans for fiber. I feed frozen peas microwaved in water, remove the shells, and squish them up every week. (I also have platies who need greens in their diet anyway). I also recommend feeding more of a variety of foods. You said "sometimes" feed freezedried bloodworms; how often is "sometimes"? I feed freezedried bloodworms to all my fish once a week after soaking them in tank water (this helps reduce expansion of the dried worms in the belly).

I really don't think it's dropsy because in my meager experience with it, it doesn't cause one little lump nor look like that, plus I looked up betta anatomy and the kidney is higher than where the lump looks to be on your betta from the photos.

 

Is the tank cycled? It could possibly be the water

 

Could be a tumor. I'm not sure.
I am worried about the nitrite. You shouldn't have any nitrites. Do you usually have nitrites or did you catch the tank at a bad time?
Also, if you've had the tank cycled for all the 9 months you've had him since February, I see no reason to add bacteria starter in at every water change. You should have bacteria already established. Unless you're doing so because of the nitrites? How do you clean your filter?

You can try feeding peas or greenbeans for fiber. I feed frozen peas microwaved in water, remove the shells, and squish them up every week. (I also have platies who need greens in their diet anyway). I also recommend feeding more of a variety of foods. You said "sometimes" feed freezedried bloodworms; how often is "sometimes"? I feed freezedried bloodworms to all my fish once a week after soaking them in tank water (this helps reduce expansion of the dried worms in the belly).

I really don't think it's dropsy because in my meager experience with it, it doesn't cause one little lump nor look like that, plus I looked up betta anatomy and the kidney is higher than where the lump looks to be on your betta from the photos.

I feel like I typically always test positive for nitrites. I did a full tank cleanout yesterday. I thought after every full change you have to add bacteria starter? I just wash the surface of the filter under water before putting it back in.
I'll try the greenbean idea. However my betta is extremely picky and I'm afraid he won't even try it. I feed him a few freezedried bloodworms a week but I haven't been soaking them.
I actually bought BugBites betta formula today and he has been eating that as well.

 

So your tank is cycled. Probably a tumor.

 

On the template you put that you change 100% of the water, every 5 days, is that true? or did you mean that you just did a 100% water change and do a different % amount every week/ month for routine maintenance?

 

On the template you put that you change 100% of the water, every 5 days, is that true? or did you mean that you just did a 100% water change and do a different % amount every week/ month for routine maintenance?

Yes I do a full clean out (100% of water) every 5 days however if I test and there is a problem I’ll do a 25% change

 

On the template you put that you change 100% of the water, every 5 days

Oh wow, I missed that! That's not good. I hope the filter isn't changed too.

I did a full tank cleanout yesterday. I thought after every full change you have to add bacteria starter? I just wash the surface of the filter under water before putting it back in

Noooo, don't do a full tank clean out because you'll remove good stuff, too! Just gravel vacuuming and doing 25-50% water changes weekly (give or take depending on the tank and fish) is good enough.
After every full change, yes, but you shouldn't need to do any full changes.
Do you rinse the filter in tank water or tap? Do you wash out the substrate too?

 

Yes I do a full clean out (100% of water) every 5 days however if I test and there is a problem I’ll do a 25% change

How did you cycle your tank? My understanding is you shouldn't be doing 100% water changes and with 100 % WC's you are restarting the nitrogen cycle, which would be why your reading nitrites every time your testing.

 

Oh wow, I missed that! That's not good. I hope the filter isn't changed too.


Noooo, don't do a full tank clean out because you'll remove good stuff, too! Just gravel vacuuming and doing 25-50% water changes weekly (give or take depending on the tank and fish) is good enough.
After every full change, yes, but you shouldn't need to do any full changes.
Do you rinse the filter in tank water or tap? Do you wash out the substrate too?

I only replace the filter if it’s basically falling apart, maybe like every 5months? I rinse with tap water.
I wash the substrate too

 

I only replace the filter if it’s basically falling apart, maybe like every 5months? I rinse with tap water.
I wash the substrate too

Then that's where you're going wrong with the nitrites. You're removing the beneficial bacteria that convert them into nitrates. Although you can rinse the filter with tap water (I always did in the past, but I had well water then), it's probably safer to do so in old tank water, like what you've removed during a water change. That way nothing harmful in the tap water can kill the good bacteria on the filter.
But I'm glad you're not replacing the filter constantly, that's probably why your nitrites aren't higher. But substrate such as gravel, decor, and even the tank walls can grow and house beneficial bacteria, too, so that's why washing the substrate completely is bad. Just gravel vacuuming to remove debris is good enough.

As for the lump, you can try feeding peas and/or other greens like green beans to try to flush out his system in case it's just constipation. I usually start to see a difference within a day. You can also fast him for a few days before giving a pea or greenbean to entice him to eat it as well as allowing his system to rest. You can fast him afterward, too. How is his poop? What's it look like?

If it doesn't get better after maybe a week (although you should start to see improvement soon), then it's probably something else.