Outside of the Diadem, mousing over a fish's icon on the left side of the in the Fish Timer window will show you the preferred bait for it and what size bite (!/!!/!!!) it is.
Inside the Diadem, or at least at the Windbreaking Cloudtop fishing hole (I have not tested the others), it does not.
(edit: I can confirm the Buffeted Cloudtop, for instance, also does not. Appears to be all Diadem fishing holes.)
Outside of the Diadem, mousing over a fish's icon on the left side of the in the Fish Timer window will show you the preferred bait for it and what size bite (!/!!/!!!) it is.
Inside the Diadem, or at least at the Windbreaking Cloudtop fishing hole (I have not tested the others), it does not.
(edit: I can confirm the Buffeted Cloudtop, for instance, also does not. Appears to be all Diadem fishing holes.)