A question about my goldfish

I have 3 goldfish and have noticed the past few days that every once and a while they will just start swimming out of control and then swim to the bottom of the tank and rub their sides on the rocks almost as if they are scratching themselves. I have looked them over and do not see anything on their scales and was wondering if any of you had any ideas as to what it might be. Thank you for you time.

That could be a parasite infection. Or, it could be something wrong with the water -- too much ammonia or nitrites in it for instance. How big is your tank? I would start by taking your water to a pet store to get it tested. If the water is OK, tell them the symptoms and ask if they have any ideas what you should treat for. If they are all doing it, chances are it is the water since that is the no. 1 killer of fish. Three goldfish should have 30 gallons of water. If there is less, you need constant water changes to prevent death from ammonia or nitrite poisoning. Good luck, I hope they feel better! (if you see no other symptoms, that is also often a sign it is the water. Doesnt mean you are doing anything wrong, though you may need an upgrade or to cycle the tank, it could be one thing that needs to be resettled.) Good luck!

PS, that is BAD advice to put antibiotics and antifungal medicine into the tank every time you change the water. A, you will make the bacteria immune to those medicines so when the fish DO get sick, it won't help. And B, giving unnecessary medicine can itself make the fish act nuts and become sick and unhealthy. It will kill off their immune system -- no wonder the guy above me has fish acting so weird. That IS NOT normal. All fish will act a little strange sometimes if they are upset or something, but they should NOT be doing this on a regular basis, and certainly should not be medicated so often!