Yes I have, I have pvc fittings they play with and I have a racket ball floating in there for them to play with as well. However a word of caution with floating balls!!!!! DO NOT USE PING PONG BALLS!!!!!! I killed an Oscar this way without realizing he had gotten big enough to swallow the ping pong ball. It was in there for months, ever since he was about 2" long. We had a blast with that ping pong ball until that fateful day when I came home and he was floating dead and bloated. It took me hours before I realized the ball was missing!! Thats why he was bloated. So be sure these play toy are way to big for them to swallow. The pvc fittings work good because they can get their mouth between the inner and outer diameter to pick them up but not swallow them due to the full diameter is like 2 inches.