We have had three of our goldfish for about 2 years now the fourth for a year and we just recently got a pleco for the alge bit. My two fan tails mouths apper swollen on the inside. One worse then the other. The other two appear normal and I have never seen the pleco go after anyone. They are all in a 29gallon tank with an air raider and one archway. Please help me this is highly upsetting to me.

yours has the exact opposite problem to mine. maybe there is a break in the jaw. have you had a close look? try touching it to see if it moves unusually. try and peer in to see if there is anything lodged inside the mouth.

First of all what kind of plecodo you ahve? Are you aware that most kinds really aren't compatible with goldfish as there is a risk that they will suck on the fish's slime coat when they mature.
Secondly, have you tested your water parameters (ammonia, nitrite, nitrate)? Most problems are caused by poor water quality so it is very important that you do this.
Thirdly, if you are sure that there isn't a blockage in the mouth (i.e a piece of gravel), are there any other symptoms? White fungussy stuff, strings blowing in and out of mouth?
Do the fish still eat and do they appear well otherwise?

The redness has gone down considerable. ooo is starting to move his mouth again and Who's lip looks ALOT better. All lvls check out fine. Changed a portion of the water. The pleco we have is the same as my father in law has and he is only if he's luck an inch long. Brownish in color. Noone seems to be botherins him and vise versa. Trust me I am watching all of them even closer now. Thanks.