Seaweed

Barely a fish at all, Seaweed is a Trash item you can hook anywhere, and the wiki adds that Crab Cages bring it up more easily than the rod does. The listed bait is Magnet (an Unusual bait). Weights run from 0.2 up to 1.3 kg, averaging 0.9 kg, and each catch is worth 20 base XP.

The wiki flags a quirk: although the catch is Trash, the Seaweed you use as bait is rated Unusual, and the two are easy to confuse. The item itself shows up as small, standard strips of dark green weed, and because of its low rarity it crawls across the fishing bar.

Among the 24 Trash items, its 1.3 kg top weight is #16, under Boot (2.7) and Driftwood (1.6) and level with Translator Core, just ahead of Rusty Hook (1.1). The 20 XP is #7 of 24, tied with Scrap Metal, Fungal Cluster and Destroyed Fossil, with Bone (25) above.

The quote is the memorable part: “Some lovely seaweed that caught your hook. Not as cool as a fish, but it's better than finding a lonesome boot!” The catch lines go downhill from “Seaweed!” to “Oh. Seaweed.” and a sad “Seaweed..”