wiggly worms in my 55 gal. tank

Question
i have very large  pacu in a 55 gl tank. he is well over a foot long . i noticed tonight there are a lot of very small wiggly worms in my tank.about the thickness of a strand of hair. where could they come from. the only thing diff i've done is change the pellet food brand. i have had this fish about 4 years in this tank

Answer
Hi Linwood,

You probably have planaria (aka flatworms) in your tank. When the gravel gets dirty with uneaten food, planaria appear, so just clean up the gravel (give it a deep vacuuming) and cut down on the food, and they will go away just as quickly as they came. You can read more here:
http://www.fishdeals.com/fish_diseases/planaria_white_worms/

You probably know this already, but your pacu should have way more space than 55 gallons! I am surprised he is not bumping himself all the time, this tends to happen when big fish outgrow their 4 foot tanks. Pacus get absolutely huge, one famous pacu named Swish (who belonged to a Chinese restaurant) weighed 32 lbs. and was 30"! Obviously, they are not fish well suited to the average hobbyists' home aquarium...(of course, that doesn't stop Walmart from selling them. It's maddening.)

Pacus are "vegetarian piranhas" so make sure to give them lots of greens, as well as fruits. Here's some ideas:
http://freshaquarium.about.com/od/feedingfis1/a/vegetarian.htm
Swish loved apples and grapes, along with carrots, so try those too.

I hope that helps, take care.
Nicole