My Plecostmus seems to float at the top of the aquarium

Question
I have a Plecostemus in a 29 gallon aquarium. I've had him for about 2.5
years. He shares the atnk with different Mollies and platty's. He was
about 1" when I got him and is now about 8-11" long. He seems unable
to stick at the bottom of the tank. He tries to wedge himself between
trees/buildings etc.. he almost seems like a balloon he frequently floats
upside down at the top of the tank. He has been like this as for a long
time and I'm not even sure that it's  wrong as he continues to grow and
has no visible damage, but he does really seem to try to stick to the
bottom and floats to tyhe top at a fast speed.  Thanks in advance for you
advice.

Answer
Hi Vicki,
Sorry to hear about the Pleco.
I would say first off that it sounds like he has swim bladder disorder, which is a condition where if a fish's swim bladder (which controls the fish's equilirbium) is not functioning properly (due to many causes) then the poor fish often float at the surface and lose a lot of control of their normal swimming. The most common cause to Swim bladder disorder is related to diet...A died that is too rich or doesn't contain enough fiber can cause an intestinal blockage which interferes with the swim bladder.

What is the current diet of your pleco? I've heard before that if plecos get too much protein, they can get sickly and start the floating condition. Sometimes even algae wafers aren't the best fiber sources for plecs, because most algae wafers are consisted of lot of "fillers" in the form of proteins.

Probably the best thing you can do now is offer your pleco lots of vegetables. Peas are well-known for helping swim bladder disorder patients but you could try other vegetables for your pleco like Zucchini. Also, make sure the water quality is clean and good. A pleco as large as yours puts a very very big bioload on the aquarium and high nitrates could be a problem. So just make sure to keep up with those large frequent water changes.

Does your pleco show any other symptoms at all? Does his belly look really bloated? Is he pooping normally? And how long has the poor guy been like this?

I hope we can figure this out and help the poor pleco!
Best wishes,
Karen~