We've had trouble in the past with being unable to remove all of the water from our squeakers and squirters, who then developed mold that could not be removed. Boo! We really hate to have to get rid of ducks, but the mold is disfiguring and disgusting. We also really hate to have to ban ducks from the bathtub, but that is what we have had to do with any ducks that have holes. It makes the tub a very lonely place.
To liven up our tub, we've populated it with species of rubber ducks that do not have any holes. Our favorites of this genre are the "Odd Ducks" offered by Boon, Inc.
Not only are these ducks mold-proof champion floaters, but they are also delightfully eccentric in shape and style. They are a big hit in our bathtub.
We did have a bit of a mold problem with one of our Odd Ducks when the bottom seal pulled away from the body of the duck enough to allow water to seep into the bottom and grow mold. However, we think this was a manufacturing flaw, as the other three don't have this problem. Boon, Inc. was awesome about handling the problem, when I emailed them about it. It's a great company, and their ducks are top-notch!
So, for anyone looking to spruce up their bathtub with a non-molding rubber duck model, I heartily recommend Boon's Odd Ducks, as well as other completely sealed rubber ducks with no holes.