there is a big risk invalved in taking anything from a beach and putting it into your tank.there are a variety of diseases that you may get from the contaminated waters of a beach or a conal.if you quarantine the fish in fresh water acompanied by amquel to declorinate the water so that all the germs are killed off the fish.but you are still at rish of getting some kind of disease.i wouldnt recomend this.but it is your choice.
kevin