How to Fish Weapon Attachments — Four Slots, Two Choices
Every gun has the same four slots. You never run both variants of a pair.
Attachments are the part of the How to Fish shop that players most often overspend on, because the slot rules are never explained in game. Every weapon — pistol, shotgun, SMG, sniper, assault rifle — has exactly four attachment slots, and two of those slots are an either-or choice between a pair of parts. Buying both halves of a pair for the same gun does nothing at all.
That matters for money as much as for damage. A fully attached assault rifle runs to roughly $54,250 with upgrades, so knowing which parts are redundant is worth real income. Weapon base prices and bullet upgrades are in Weapons & Rods.
The four slots
| Slot | Options | Notes |
|---|---|---|
| Extended magazine | Extended mag | Single option, always buy |
| Laser sight | Laser sight (~$100) | Single option, big hip-fire gain |
| Optic | Red dot or sniper scope | Pick one |
| Muzzle | Compensator or suppressor | Pick one |
The extended mag and the laser sight are straightforward: there is only one part for each, so both are pure upgrades. The optic and muzzle slots are where money gets wasted. A red dot and a sniper scope compete for the same slot, and so do the compensator and the suppressor. You fill one of each pair and the slot is complete.
Attachments can be fitted from Island 3 onward in principle. Island 4 is where the pool finishes filling out, because the sniper scope and the suppressor are added to the shop stock there. Since you only ever mount one optic and one muzzle, those late additions change your options rather than your requirements.
Which options to pick
For the assault rifle you intend to bring to the final boss, the suppressor is the stronger muzzle choice. Paired with the laser sight it gives excellent hip-fire output, which is what you actually use while strafing lava pools rather than carefully aiming down sights.
The compensator earns its place earlier. It tames recoil, which is exactly the problem an upgraded pistol or a bare SMG has — SMG recoil is rough enough that a muzzle part is close to mandatory before a boss fight. If shots are landing and the health bar barely moves, buy damage instead; if shots are missing, buy control.
For the optic, the red dot suits close and mid-range work: the shotgun and SMG fights on the Forest and Desert islands. The sniper scope exists for one fight in particular. The Albatross stays airborne at long range where shotguns barely reach, and single accurate shots at that distance also feed the 360 no-scope multiplier described in Killscore.
Fully equipped achievement
Fully equipped pops when a single weapon has one attachment in each of its four slots at the same time. It does not care which weapon, and it does not care which variant fills the optic or muzzle slot. A rifle running extended mag, laser sight, red dot, and compensator is complete even though the sniper scope and suppressor also exist.
That means the achievement is technically available from Island 3, well before the sniper scope and suppressor appear. Most players wait anyway, and the reason is money rather than availability: income on the Volcano island is far faster, so it is cheaper to finish the build there. The Goblin Shark alone sells for roughly $9,300 lava-cooked, as listed in Fish Prices and Mini-Bosses.
Build it on the assault rifle. You want that gun fully kitted for the lava whale regardless, so the achievement arrives as a by-product of preparation you were already doing. The rest of the list is in All Achievements.
Buying order
Bullet upgrades first, then the muzzle part that fixes your current problem, then the laser sight, then the extended mag, then the optic. Upgrades are per weapon rather than account-wide, so pouring money into a pistol you plan to replace is the classic beginner trap — the tier comparison in Gear Tier List shows which guns are worth investing in. Note that weapon upgrade prices are cheaper in solo than in multiplayer lobbies.