+1 Drain Water Per Click Mutations Guide

The four multipliers

A mutation raises the sale value and earning rate of a fish you have just discovered. The set is Gold, Diamond, Venom and Hole, and the multipliers below come from a public snapshot dated August 20, 2026:

Read the name above the fish, not the colour. Roblox lighting can tint an ordinary catch enough to fool you, and the label is the only thing that settles it.

These are dated snapshot values, not a permanent odds chart. The developer has never published a mutation table, exact spawn percentages, or area-by-area rates — so if the number above the fish disagrees with this page after an update, the game is right and this page is stale.

One mutation per fish

A fish carries one mutation at a time. They do not stack, and mutation rules from other Roblox titles do not carry across — a pet mutation system or a crop mutation system in a different game tells you nothing about this one.

Poison and Black Hole weather

Two weather events are reported, and they pair with the two rarest mutations:

• Poison weather → improves the chance of Venom fish spawning.
• Black Hole weather → improves the chance of Hole fish spawning.

Both are reported at a +10% spawn-chance boost over a four-minute duration. Those numbers come from the same August 20 snapshot and have never been confirmed in an official event description, so treat the duration and the size of the boost as approximate.

The important mechanic is what weather does not do: it affects the chance of new mutated fish spawning. It does not re-roll a fish already sitting in your aquarium or your backpack. Saving an ordinary catch in the hope that Black Hole weather will upgrade it is wasted backpack space.

How to actually farm mutations

1. Run your normal Water and pool loop — mutated fish come out of the same drains as everything else.
2. Drain fully, then check the label above every new fish before you move on.
3. Collect a mutated fish quickly; it can despawn.
4. Scan each new area rather than camping one pool.
5. When Poison or Black Hole is active, spend the whole window on fish that spawn during it.

Gold and Diamond are described as the more likely natural spawns, so you will meet them without waiting for weather. Venom and Hole are the ones worth reorganising a session around.

Where the value actually lands

A mutation multiplies what a catch is worth, and that value shows up in two places: the Cash you get for selling it, and the per-minute income if you put it on display instead. That makes a Hole fish the strongest possible aquarium occupant, not just the best sale — see fish and selling for which of the two to pick.

What is still unknown

No public source has published the base spawn rate of any mutation, whether rates differ by pool, Area or Lake, how often weather events trigger, or whether the multipliers apply to the sale price, the aquarium rate, or both at the same ratio. Those are open questions, not secrets someone is withholding — and this page will say so until a source exists.