red sore on alge eater

Question
I nreturned home today to find my alge eater with a red sore on it this is a new 10 gal tank and all I have is seven guppies 2 female and the rest males. I brough two new fish yesterday.I only use bottled water for my tank. The alge eater is eating and swimming the same what could be the problem.

Answer
Hi Rhondiez,
Have you checked your water chemistry?  Check your ammonia, and nitrate level.  Bottle water is not good for any fish.  You are better to use tap water with a good conditioner. (Stress Coat would be very good to use, and helpful for your Algae Eater.)  It is not a cure, but would help his skin.  Bottled water lacks the minerals that a fish should have, and sometimes contain metals that are harmful to fish.  A sore may be related to many things, and one of them is stress.  Does he have a hiding place where he can go?  Do you feed him?  A pleco should be fed like all other fish.  You will find special food for him at the pet store.  Many people think that they don't have to feed a pleco, that he will find food at the bottom of the tank.  This is untrue, and cruel, as many starve to death.
 Water Chemistry could be the cause.  It would be well worth it to invest in these kits, as ammonia is the number one killer of fish.  
Your ammonia and nitrate level should be marked safe.  If they are not safe, do water changes until they are.  You should change 25% of your water every week.
When you get your ammonia and nitrates down to safe, buy "Malafix"... follow the instructions on the bottle.  Make sure that you shake the bottle well before using. This is a natural medication, and should help.
I would also like to mention that 2 females to 5 males is not the right way to go.  The females will constantly be harassed by the males, and sooner or later will bring disease to your tank.  Stressed fish bring disease, always, there is no exception to the rule.  It should be three females to one male.
Do not overstock your tank.  The rule one gallon to one fish is not the right way to go.  Fish need place to swim, and oxygen.  The guppies have babies very often, and they grow to almost 3 inches in length.    Don't add anymore fish to your 10 gallon tank, if you do, there will be problems.  I thought I would mention this, as I know many pet stores don't inform people, they are there to sell, and many don't care.
When everything is back to normal, and your Agae Eater is well, you may add two teaspoons of aquarium salt to your tank.
Hope this helps
Lynda