Get your wyvern/crystal wyvern, goto crystal isles to the scorched earth part of the map with the giant archways, lots of sand next to the ocean, find the arthropluera you want, pick it up, take it to the ocean and hang it in the ocean and get off the wyvern, feed it spoiled meat amd go from there, usually for me the ocean is extremely clear, the arthropluera wont keep moving nor will it drown, though if this doesnt work for you its because you are doing it wrong.