sick plecostamus

Question
QUESTION: I have 2 plec's one is 5yrs & 12" long the other is 2 yrs and 8" long. The older one has been acting funny by swimming fast & erratic around the tank like he has a fit. There is a small white spot on his chest but it doesn't look fuzzy. the younger one is just starting to do this behavior but doesn't have any white spots. My tank is 55gal. I do gravel cleaning usually once every 2 weeks. I have 6 platys, 2 angels, 1 gouramy & 3 aust. rainbows in the tank also. My water temp is 80 deg. I do water changes once every 2 weeks when I clean the gravel. I tested for nitrate levels and they are all good. I would appreciate your help in solving my problem of a spasing plec.

ANSWER: what do you feed your plecos' and how often do you feed them???

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QUESTION: I feed them a variety of things lettuce cucumber algae disks shrimp pellets melon they love watermelon.I usually sprinkle some shrimp pellets once daily or algae disks and they get veggies once every three days.

Answer
Pleco's can become very territorial... usually I recommend one per tank.  You may have a pair that might be trying to mate... or just two males fighting over territory.  I would just keep my eye on them and see if it gets worse... if so I would separate them...  if they are up-setting the fish then I would separate them too... if not... just let them be.   dave