Firebelly Bloat or Dying?

[Ephemeral]

Hello, everyone. New Jersey newt owner.

First time poster here. I hope that you guys could answer my question.

I've had my duo of fire belly newts for five years now. But something has changed within the girl of the pair.

As far as I can tell, she does not have bloat and she does not have any injuries.

I was changing the sponge of the filter, and usually I am able to shoo the newts away from the filter when I go to lift it out of the aquarium.

Usually the girl newt is obnoxiously curious because of possible food and I have to gently scoop her aside.

But instead of her usual behavior of letting me scoop her up and set her on the island, she has suddenly seized up and curled into a "C" shape. She became stiff as a board like she just up and died.

I thought she had a newt heart attack or its equivalent.

I checked to see if she was breathing, and after a moment of lowering her on the island, she slowly went back to normal.

I tried researching "playing dead" or this sudden "stiffening" but it seems like I get a bunch unhelpful articles.

I've been trying to avoid her awkward charges for food since I'm afraid she'll just "play dead" too hard and be real dead next time.

Is this a normal newt behavior I never heard of?

Is it a symptom of a disease?

I moved her out of the tank because she flopped upside down and is acting pretty deadish.

Thanks in advance.

And she's dead.

I don't know what killed her, but she's officially dead.