Whydoes fisher have no native abilities that cost GP, and only one learned ability?

[Conradus]

I guess it's worth noting that the tooltip for the buff doesn't even say anything about shards/crystals and just says yield is increased under thunder affinity or something like that. Do any fish have elements associated with them?

Actually, it doesn't say that. Perhaps it's been changed since you last read it. When I read it a couple of days ago, it read "Increases shard yield" (period) Not even crystals or clusters. Just shards.