I'm having problems finishing the [Fishing Leap Skilled 10] Nothing's Good quest because I'm not able to submit the 10 Blue Grade Fish Ario wants. I have at least 2 different blue fish in my bag and still his Chat option to accept them is grey.

And these are the blue fish from the Calpheon region?

Yep, me too.

Yep, had an Eel and an Arowana... also it should just accept ANY blue fish if it asks for it i would think...

Edit: I'm not sure why this was moved from Feedback since this is clearly a bug.

I am having the exact same issue, the quest NPC Ario does not accept any kind of fish, neither green nor blue, which I have fished from the Calpheon River and which are fresh and in my inventory. The NPC acts as if I had no fish that fit the criteria in the inventory. Before this quest was changed to green/blue fish it used to work (the quest originally wanted yellow-grade fish). Please fix this bug.

i do not know if this will help at all. but i think i did this quest recently. 

there is a yellow circle that shows up on the docks (i assumed that is where i am supposed to fish so i fished there). i did manage to get 10 green and 10 blue and hand them in. maybe the fish have to be fished out of this yellow circle area at the docks? i could be wrong so forgive me, but hope that maybe this might help.

The yellow circle actually shows where you can fish to get these fish. Also, as mentioned above, the quest did work before it was changed. This is a simple case of Pearl Abyss changing the quest requirements and not adjusting the NPC who receives the items (it used to be two specific yellow-grade fish, it's now general green and blue grade fish).

I was in contact with PA support and the solution was to have all TEN fish of the green or blue the inventory, on then you can hand them over. This is a change from how the quest was before, where you could hand over each fish individually. If you still have the quest open from before they changed the quest you need to forfeit it and re-accept it.