hhmm.. what do i do with this fish?

[lebirath]

hey, so leveling my fisher i have come alone with some fish that online doesnt no seems to know a use for them... (mainly gamer escape and eorza app)
so far:
chub
gudgeon ( http://ffxiv.gamerescape.com/wiki/Gudgeon )
dwarf catfish

there is no point to put them in the market.. so, just sell them to npc? anyone knows any use to these? or another source??

thx..

EDIT hmm... i have a few other question bout fishing, guess should have put the title as "fishing".. sorry

1. how do i know which fish can be use as bait? cant figure out how to know that a fish that i catch can be bait (meaning before turning it into a bait by recipes)

2. There are fish that have differrent "grade" e.g. http://ffxiv.gamerescape.com/wiki/Crayfish .. but i dont get why would someone would like a higher grade; it seems that u need more perception (especially to make it HQ quality) and the recipes dont seem to distigue between both of them (based in akchemist and culinary recpies up to lvl 30)

thx again..