yes you need to find a red shard and take it to theshard collecter to the right of mossedeep city he will trade you a stone for a shard.
yellow= thunder
red= fire
blue= water
green= leaf
you can also cacth shards off of Clamperls holding Blue Shards
Relicanth holding Green Shards
Corsola holding Red Shards
Wild Chinchou holding Yellow Shards.
