[byron]

Hey I found these nive rocks the other day but i noticed that some had rust color stains on them. Do you think they are safe for aquarium use? And also what do we have to look at physically for a rock to be safe for aquarium use?

 

[Blackbar]

General rule, don't put anything in that looks rusty or reddish.

 

[onefishtwofish]

it is more than likely iron...not recommended as above

 

[oscar]

if in doubt throw it out! rust is toxic to fish.