growth on betta

Question
This is my first fish ever so I'm am totally clueless of what's going on.  I've had my betta for about a month and everything has been fine so far.  I completely changed the water in his filtered 1 gallon tank yesterday and today I see something under him that looks like a growth.  It actually looks like a food pellet attached by a very fine string.  But I feed him flakes so I know it's not a pellet.  He looks uncomfortable with it because it's right under his fin.  What could it be and what should I do about it.  I'm worried I hurt him by changing is water but it really needed it.

Thanks a million

Answer
Hi Natasha;

The water change was just fine and a very important thing to do. Your fish actually needs it every week. If the thing under him looks like it is attached to where his poo comes out, it may mean he is constipated. The very fine string could be mucous from his digestive system and the "pellet" could actually be some impacted food that he has pooped out. There may be more inside him and that's why he's uncomfortable. Here is a web page about it so you can treat him;

http://bettas.fishjunkies.com/Disorders/constipation.php

At Your Service;
Chris Robbins