skip sole all together would be my advice.
Have my main @100 fishing and mule at 96 never fished up a single sole.
Not sure of your lvl so ill give you a list of what I found the quickest for cash/skill.
55-96 tallaca cove fish for ahtapot's mercabligi and dil lu shang+shrimp lure can make 130-150k a day just NPCing them. For greatest profit NPC them in whitegate fishing guild.
96-100 Armored Pisces they NPC for 940-1k if I remember right.
Once you got 100 fishing lvl bonecraft to 89+ and fish trumpet shells craft to rings and NPC for 360k per day instant profit. Made over 120mil doing this with both my fisher's in just 6 months.