I've used silica sand that I bought from a pool shop with plecs, loaches, ropefish (same family as bichir,) and loaches for almost a year with no ill effects.
They eat the stuff, dig through it, and pass it with no issues or worn barbels.
Just remember ya need to stir it once a month to prevent anaerobic areas that product sulfide gas (that fart smell.)
I use kiddies play sand purchased from the local Argos store for the cheapo price of £2.49 for 15kg's. I gave it a quick rinse when i bought it but it was dust free straight out the bag. And as they state : Sand is washed and graded. & Non-toxic and non-staining.
Its been great in my tanks and the multitude of fish seem to all love it. Be it digging or hiding or just 'playing'.