oscar tank

Question
I have noticed small white worms on the glass and in the water.  The water won't clear and my two bottom feeders--shovelnosed catfish and pleaco have died.  Now, when I turn the light on at night, I have found these little tiny silverish tadpole looking creatures swimming around in the tank.  I have a 20 gallon with a penguin filter suitiable for up to 55 gallons with double cartridges in it.  I have one airstone in the tank.  What is going on with my tank, and how do I fix it?  I love my fish and it hurts to see them perish.  Please help.

Answer
Hi Eve,
The problem is actually simple: you need to be doing more frequent water changes. If you do that, the white worms will go away.  Do not treat the tank with a bunch of medications.   You need to be changing 25% of the water once a week, EVERY week to keep your fish happy and healthy.

 Also be sure that you are not overfeeding.  Never put in food for the fish to "eat later".  Only put in food that they will eat right away.  

  One final thing: a shovelnose catfish grows to over 3 feet in length. You want to think carefully about which fish you put in a tank.  The oscar will grow to between 12 and 16 inches in size and will soon need a tank of at least 50 gallons, 70 or more would be better.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>