The mops are usually used for killies but you can use them for guppies. Yes they work.

thanks Cityworm, do they hang down in the water or float flat on the surface do you know?

Big Al

They are made either way. Some people have corks attached to them so they will float.Some have suction cups attached so they will not float around the tanks. Its up to you.

I used them when I was breeding bettas for the female to hide in in case I couldn't get her out the minute the breeding stopped. I made my mops the color of the female so she could hide better from him. I think it is better than using plastic plants because she doesn't rub her slime coat off when dashing into them.

I wrapped yarn around a small book cover until I had it about 3" wide. (I used a book because it was stiff, conveniant and slick enough to slide the yarn off easily.) I ran one piece of yarn between the book cover and yarn crosswise and tied it tight. then slid the yarn off of the cover. If it was a floating one I put a small styrofoam ball at the tied end under the yarn and tied the yarn again under the ball. If it was a sinking one I used a marble in place of the styrofoam. Then cut the bottom off so the yarn wasn't looped on the other end.
Use acrylic yarn, not wool or other natural fibers.

I made mine the same as Jennifer and used them when I used to spawn fancy goldfish in aquariums.