You're welcome :), so since your current shark is Bull shark. I think, you shouldn't use him in to grind in Arabian Sea because of at there a lot of stronger and powerful sharks spawn such as the enemy meg, GW and Tiger sharks that can kill your bull s while grinding for gems. I think if you want, try grinding in Arctic Ocean. It's more safe and still good to grind a decent amount of gems like 26-30 (if you're lucky).