Question
Dear Brigitte,
    Hi, Could you please tell me are bricks or cinderblocks safe for fish?  I wanted to raise some of my potted plants in my pond and I was wondering what would be safe for the fish.  Thanks.
Susan

Answer
Hello Susan!
Generally bricks are pretty safe, we use them quite a bit. Problems can occur if the bricks have been sprayed with insecticide or herbicide or some other chemical that can leach into the water.
Cinder blocks tend to alter the water chemistry and may make it harder to balance the pH.
We have found that clean terracotta pots turned upside down make wonderful stands for aquatic plants in the water.
/Best regards
Brigitte/www.pondmarket.com