i'd say tread with caution. if you've used craft ones and they've been fine then that's great, but do take care as you've no idea what chemicals are in them and what will leach out. you can see the dye, but there could be other chemicals you can't see. the effects will be more apparent in smaller tanks as the leaching is more concentrated. i'm quite a cautious person, so i'd still with those which say aquarium on them!!
That will definitely work to keep the dye from running but craft store silk plants have wires in them and they will rust. artificial plants made for aquariums is really the only way to go.I currently added artificial plants from walmart without a problem. I used a trick that my grandma showed me. She used to add vinegar to some water with a bit of salt (I didnt use iodized) then put the clothing in. This would set the dye into the fabric or leach the loose dye out (not sure). The dye in the fabric would never again run. I tried this with the plants, soaking them overnight, rinsed them well and then I placed them in my tank. its been several days and everything looks fine so far. My fish love them, and it was considerably cheaper.
I took the wire out of the plants. So check on that factor. So the dye can leach out and kill fish?
ya that's where I saw the pictures to cause me to ask the question. I went right over it... it was on the first page... I was pictureing way older... I mean I thought it would take decades to get up to 18,000 posts and become a Master of Fish Poo