Rock Questions

[celaeno]

i just bought 7 river rocks and 1 carved rainbow rock from the lfs. i scrubbed each rock in a bucket of warm water.

each time i put a river rock into the tank, oily swirls appear on the water surface. is this dangerous to the fish?

the carved rainbow rock has two holes in it and is from feller stone. there are some black deposits on the corner that i can't get off with the toothbrush. any idea what it is and how to get it off?

here are some photos of 3 of the 7 river rocks. after boiling them for 20 minutes and leaving them in the pot overnight, they still release some oil when submerged.

the first 3 pics are the 1st rock, the following 2 pics are the 2nd rock, and the last pic is the 3rd rock.

rocks

 

[Inchworm]

Hi celaeno

The pictures of them look shiny, and if that's not just because they were wet when you photographed them, they may be coated with something not suitable for use in and aquarium. If you are in any doubt about this, it would be best not to take a chance.