De worming a puffer/ and spot on fin question HELP

[darbronnoco]

I guess my first question is....what is deworming and how do you do it. I have a puffer and I hear they may need this. How do I tell when they need it and How do I do this.
My secone question is. I have a huma Trigger and he seems to have this large white spot on his fin. I don't think it is ick. no one else has any signs, and my trigger is swimming like nuthing is wrong. I think it has gotten a little larger.
I am by no means a newbie, but I haven't really seen anything like this before. Pleas help! Thanks alot, Brad

 

[beth]

Is the spot on the fin scar tissue, or just a malformation of the fin from, perhaps, aggression?
Deworming? Sounds like what you do to cats and dogs to me.

 

[darbronnoco]

THe trigger also has what looks like a laseration on his lower fin. I haven't noticed that getting any bigger. The white spot is still there. Does anyone know what this deworming thing is?
HELP
Brad