I can't get a good picture of these things, but I'll describe it as best I can. In two of my three tanks, I've noticed what appears to be some sort of insect.

These things are the size of a grain of sand - probably even smaller. They just look like a tiny rust-colored speck. I see them moving on the tank walls during water changes...and you can see them occasionally skipping off the surface of the water.

I have absolutely zero illness in either tank...jst fat happy fish.

So what are these things, even though everyone is healthy...should I be concerned about anything, and does anyone know a way to kill them off without stressing the fish?

thanks all!

Wow...I stumped everyone????

Nope, I just saw this thread. =P

They are usually some kind of copepod. If you can catch one and sort of feel in inbetween your finger tips and it feels like a hard grain of sand, then it's definately a copepod. They are no big deal and are like free food for your fish. Copepods are a very small crustacean. If you do want to get rid of them, then slow down on how much you are feeding your fish. They are brought on by overfeeding. With no food source for them and your fish eating them, then they will die off.

Awesome. Thanks ARB.

I'll bet that's it - I'm a notorious overfeeder. Good thing I do so many water changes.

Thanks...good info.

You're welcome! I get them in my guppy grow out tank and 30 gallon.