Hi, so we have fancy goldfish in a tank with gravel substrate, and are upgrading them to a much bigger tank. I was wanting to set up the new tank with a sand substrate this time, as heard that gravel can be dangerous to fancies as they can either injest or choke on it...and I have seen my black moor have one choking episode.
The first sand I got the colour looked much darker and very 'mud like' when in the tank (after much washing). So i got a white sand instead...however have washed it at least 20 times today and it has a scum like foam of floating sand on the surface. My plan is to leave it in the bucket overnight and see if it settles, but I don't want to put it in the tank like this.
Any advice on how to get rid of this, as washing isn't making a difference? Or any recommendations for different brands, or different substrate for goldfish? picture attatched. Many thanks.