Tiny White Parasite Looking Creatures Stuck on My Fish Tank Walls

Question
Hello Chris,

My fish tank has been set up for approx. 4 1/2 to 5 years. It's 32 gallons, glass, and I have two Lion Head Gold Fish.

My levels read as with in normal range.

My question is: I have these tiny white, almost transparant oblong-ish things stuck to the front and back inside of tank. Through a magnifying glass the center (or gut portion) of these creatures is dark.

We noticed them about 1 month ago, but there were only 1 or 2. Now, 10 or more. My fish seem fine and uneffected, but I'm worried that this is the beginning of something that might hurt them. I want to head it off if possible. Do you have any idea what this might be? If you push them, they stay stuck and can be pushed about on the glass with out detaching themselves. If I take the edge of my cleaning brush and crush them, they will detach and the dark stuff in the center comes out.

I really love my fish, and want to protect them from anything that could cause them harm. Do you have any idea what this is, and if I should be worried? I bought two live plants back in June or July 05 at Pet Co. but didn't see anything weird at that time. Do you think they came in on the plants?


Thank you for your time,
It means alot that you are here and willing to help us "Fish People" out.

Sincerely,

Bonny, Moby, and Gilligan.  

Answer
Hi Bonny, Moby and Gilligan;

The little critters are planaria and are totally harmless to your fish. They are however a sign that some overfeeding has been going on. Planaria thrive on waste. We all overfeed from time to time. We just have to clean up after ourselves once we realize. Sometimes it isn't that we put too much food in, it's the quality of the food itself. Many goldfish foods are of low quality which means they have cheap ingredients as filler that the fish can't digest very well. This means excess waste builds up in the tank as they 'poop' it out.

Goldfish are major waste producers so feed them a good quality pellet along with vegies like peas, squash cucmber, romaine lettuce and green beans. Cook all but the romaine slightly until a bit soft. The vegies are for good digestion and they also satisfy the need for foraging and nibbling. Vegies are not going to rot and make food for the planaria either. These foods can stay in the tank for several hours while they are nibbled away.

You will want to do some vacuuming of the gravel to get rid of the waste that is in there now. Do the vacuuming twice a week for the next 2 or 3 weeks. Replace 25% of the water and vacuum at the same time. You may start to see more planaria at first as they become more brave in trying to find food. They will eventually starve out and most will go away. If you ever start to see them again, cut back on food again. In my experience, a tank that once had planaria is never totally clear of them. But, they don't hurt your fish and are a good warning sign that we are getting too generous with the food can.

At Your Service;
Chris Robbins