This is a discussion on Pleco's and hard water within the Catfish forums, part of the Freshwater and Tropical Fish category; -->
Pleco's (all species) and hard water, yes , no, maybe? Any side affects?...
The answer depends upon the fish species and the "hardness" of the water. Many pleco are wild caught so attention must be paid to their habitat water parameters. But some are far more adaptable compared to other fish species.
You can start with our fish profiles--pleco are in the "Catfish" section--and the profiles are under the second tab from the left in the blue bar across the top of the page. Some of the more commonly-seen pleco are included. If yours is not there, let me know the species and I'll try to assist.