In Abyss, certain quest items are far rarer and more confusing to obtain than standard fish, and Fish Bone is one of them. If you are progressing through Ancient Sands, you will eventually run into quests that require this item. So, to help you with that, this complete guide explains exactly how to obtain Fish Bone, how the mini-game works, and where it is used so you can complete Marcus’s questline easily.
How to Get Fish Bone in Abyss

Fish Bone can only be obtained while fishing in Ancient Sands in Abyss. The process is identical to catching Geodes elsewhere in the game, with one important difference. When fishing in Ancient Sands, the Geode reward is sometimes replaced with a Fish Bone instead.
While fishing, a Treasure Chest icon can appear on the mini-game bar alongside the standard fish progress bar. This happens fairly often, roughly once every five fishing attempts on average. When the Treasure Chest icon appears, you need to fill its internal bar before finishing the main progress bar. If you complete the fishing mini-game without filling the Treasure Chest bar, you will not receive the additional reward.
To maximize your chances, first fill the main fishing bar to around seventy-five percent. Then shift your focus to the Treasure Chest bar until you see a check mark. Once that is done, return to the main bar and finish the mini-game. When fishing in Ancient Sands, this successful chest completion can reward you with a Fish Bone instead of the usual Cactus Geode
How to Use Fish Bone in Abyss

Fish Bone is primarily used as a quest item for Marcus, the Archaeologist located in Ancient Sands. His questline requires Fish Bones at multiple stages, making them mandatory for completing the questline. Below is a complete breakdown of Marcus’s quests that require Fish Bones:
| Quest Name | Fish Bones Required | Rewards |
|---|---|---|
| Deeper Analysis | 1 | $1,600, Star Shards, Small Oxygen Pods |
| Shifting Evidence | 2 | $3,850, Speed Potion, Basic Oxygen Pods |
| Beyond My Reach | 6 | $7,800, XP Potion, Cactus Geodes, Burger |
In total, you will need 9 Fish Bones to fully complete Marcus’s questline. Along the way, you earn valuable money, oxygen upgrades, potions, keys, and geodes.
Frequently Asked Questions (FAQs)
Fish Bone can only be obtained while fishing in the Ancient Sands region through the Treasure Chest mini-game.
No. The chest mini-game guarantees a special reward, but in Ancient Sands it can be either a Cactus Geode or a Fish Bone.
You need a total of 9 Fish Bones to complete all of Marcus’s quests that require them.
No. Fish Bone is a quest-specific item and cannot be sold, traded, or used outside Marcus’s questline.
For more on Abyss Roblox, check out All Fish in Spirit Roots (100% Bestiary) – Roblox Abyss or All Fish in Ancient Sands (100% Bestiary) – Roblox Abyss on Pro Game Guides!