They are gold medallist poopers! They never stop eating, so they never stop pooping. The first couple of years I fought it almost daily with battery operated vacuums (I went through several) in between my twice a week water changes. Now the poop doesn't worry me- I still do my twice a week water changes (thoroughly cleaning the gravel as I go), and I point the circulation pump at any 'tinsel' that may be draped over plants, but that's it. If it's sitting on the substrate it can wait until the next pwc. The poop lets me know they're healthy (or not as the case may be).
The only fish I've had that was a worse pooper was a comet.