wow I just order the same exact toy from Amazon :). I was searching for helium sources online as your doing but with both arabic and english. As you mentioned they only guide you to big tanks or to shops that sells the ballons. I did ask a lady in landmark about the price to fill in my RC fish and she said 90 Riyals!!! but she maybe have misunderstood me. Any way, if you get lucky with your RC fish please let me and let me know how it goes when you test run it