The fish for Ebisu+1 quest, namely: Dragon's Tabernacle, Quicksilver Blade, Phantom Serpent*, Cameroceras, Ancient Carp, Tusoteuthis Longa, & Remora (unsure about Matsya, but I don't think it applies to Matsya) cannot be caught until you are Expert rank in fishing.
I tried to catch each of them and cast (with the appropriate bait, weather, etc.) 20-50 times each, never got a single one to bite on my line. Including with Serpent Rumors and with the quest active.
I got 98, passed the guild test, and instantly all the fish were biting.
One other note: it is possible to catch all these fish at 98, though IMO it's highly advised to get advanced fishing support, the stall, and all the gear you can. They're rough at low levels.
*Not sure about Phantom Serpent, since I wasn't able to get the livers before hitting 98.
