Quick answer
Confirmed Fish-family claims, collection checklist/status surface, and explicit roster/ranking gaps.
Start with the confirmed rare/legendary Fish wording, then use the collection checklist/status surface to capture details as you find them. This is a Fish-family and collection status answer with visible rare/legendary wording, roster gap, and safe checklist behavior; the named roster and exact ranking remain explicit gaps.
For +1 Drain Water Per Click fish collection, record the Fish name and rarity first, then add its pool or Area only when that location is shown in-game.