HELP! red worm betta

[pattyfurg]

My Betta has been acting REALLY stressed put so I put him in a 5 gallon with dechlorinated water and tested the water. Ammonia was at .50 so I did a water change on the rest of my bettas and then when I went to check on the stressed out one he was darting around everywhere and smashing into everything and there's this little red worm-like thing coming out of it's lip thing :S
He seems to have calmed down now but I feel like he's in a lot of pain...
Please help?

 

[pattyfurg]

Pictures

 

[Oceangirl]

its a parasite, I can't remember what it is called.

 

[pattyfurg]

He died... The worm thing actually wasn't moving and then in a few hours it went white :/