Betta's tail quickly rotting, more info in the post!

My betta, Ender, had some mild finrot for a few months and in July his fins started to slowly get tiny bits of new tissue. I've been spending all money available for any medicine that could work and I thought it was over, I just needed to continue the water changes and he'll be healthy again.

Now, around a week ago Ender started to become lethargic and depressed, but I've just noticed his tail is very thin and it's surrounded by black rotting flesh.
Somehow he got finrot again even though I've been doing so many things that can help him.

The first collage is a month after he got it.
The second two is when he started growing new tissue and he was active and happy.
And the last is today, you can see how thin the tail has got within a few days and now he just lays completely flat on the ground and doesn't use his log, he loves his log!
Is there anything I can do for him? Is it possible to save him?

Edit: Another thing I noticed about Ender is that whenever he tries to swim up, he uses all of his energy and he immediately sinks down.
Hope this helps a bit more!

Sorry, would you copy/paste and fill in this template please so we have some more information to go off? Also, is he in a quarantine tank now, the one that looks to be bare-bottom?


Tank size:
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp:

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Volume and Frequency of water changes:

Chemical Additives or Media in your tank:

Tank inhabitants:

Recent additions to your tank (living or decoration):

Exposure to chemicals:

Digital photo (include if possible):

Tank size: 5
pH: 7.6 (I can never bring it down)
ammonia: 0
nitrite: 0
nitrate: 0
kH: The API test kit doesn't have these, so I don't know them
gH:
tank temp: 79°F

Fish Symptoms (include full description including lesion, color, location, fish behavior): Pale colors, rotting fins, slow or fast breathing sometimes, lays down on the ground all day or vertically floating on the side of the filter, barely comes up for air and if he does, he takes 7 gulps of air over and over again, he doesn't come up to get food so I have to hand feed him and he'll only eat bloodworms and they're a treat, so I don't have a good plan for his breakfast and dinner.

Volume and Frequency of water changes: I'm giving him a EM Erythromycin treatment and it says to do 25% to 50% every two days.

Chemical Additives or Media in your tank: No filter cartridges because of the medicine and I going to get some more paraguard for him.

Tank inhabitants: Nothing except him.

Recent additions to your tank (living or decoration): The only thing is a new almond leaf every once in awhile.

Exposure to chemicals: Nothing that I'm aware of.

A picture from what time? Like today, or a better before picture?

It's odd that your nitrates are at zero. My understanding is that usually a cycled tank will have nitrates above zero. Do you know if your tank was cycled? How long have you had it?

hansgruber7 said:

It's odd that your nitrates are at zero. My understanding is that usually a cycled tank will have nitrates above zero. Do you know if your tank was cycled? How long have you had it?

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The nitrate was pretty yellow, I've had this tank running since March.
There's no sign of anything bad in the water.

Can I just check with you - you are shaking nitrate bottle #2 and then the test tube like the instructions say?

Is the bare-bottom tank in the last photo a quarantine tank? What medications have you used? Sometimes using more than one medicine in quick succession can be hard for a weakened fish to handle.

essjay said:

Can I just check with you - you are shaking nitrate bottle #2 and then the test tube like the instructions say?

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Yes, I am.

hansgruber7 said:

Is the bare-bottom tank in the last photo a quarantine tank? What medications have you used? Sometimes using more than one medicine in quick succession can be hard for a weakened fish to handle.

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Especially one with a labyrinth organ.

HoldenOn said:

Especially one with a labyrinth organ.

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Then what one should I use, Paraguard or EM Erythromycin?

@PheonixKingZ ?

Definitely fin rot. You said you fed him blood worms... are these live? Dehydrated?

Paragaurd can work for fin rot, but I will discuss that later, after you answer the blood work question.

PheonixKingZ said:

Definitely fin rot. You said you fed him blood worms... are these live? Dehydrated?

Paragaurd can work for fin rot, but I will discuss that later, after you answer the blood work question.

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They're frozen bloodworms.

Kiwi_8 said:

They're frozen bloodworms.

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Freeze dried or just frozen? (This is important)

PheonixKingZ said:

Freeze dried or just frozen? (This is important)

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Just fresh bloodworms in a freezer, he doesn't really like the freeze dried ones.