The personal aquarium in Fisch pays you whether you are fishing or logged off, which makes it the strongest passive income tool in the game. A fully stacked tank of heavy giant fish can clear over 6.2 million C$ every hour, and getting there comes down to three things: which fish you slot, how much they weigh, and how many multipliers you keep active.
Quick answer: Fill all ten aquarium slots with unique high-value giant fish, keep active food buffs running, and maximize each fish’s weight through weight and size buffs before placing it. Ten optimized giant fish plus food buffs took one setup from 3.1M to 6.2M C$ per hour.
How aquarium profit is calculated
Every fish in your tank earns money on its own, and that income continues while you are offline. The hourly credit rate for a single fish follows a fixed formula:
Hourly profit = (Fish value × Weight × Multipliers) ÷ 5
Because weight sits directly in that equation, a heavier copy of the same fish always pays more. Shiny or Sparkling traits each add a ×1.5 multiplier, and food buffs stack on top. This is why the goal is not just rare fish, but heavy, buffed, unique fish in every slot.
Two other numbers move alongside credits. Aquarium XP equals 20% of a fish’s base XP per hour, and item output is rarity multiplied by a base rate per hour, topping out around 77 items per hour with a Fragment-heavy layout. If money is your target, prioritize value and weight over item or XP picks.
The ten giant fish that push a tank past 6.2M C$
A ten-slot lineup of giant fish, secured through a trade for a high-value item like the Purr of Rebellion sword, raised one tank’s rate from 3,173,747 C$ to 6,241,731 C$ per hour once food buffs were applied. The standout is the Bloop Fish, which alone weighs over 11 million kg and earns the most per hour. Here is how the individual earners break down.
| Fish | Rate (C$/Hr) |
|---|---|
| Giant Gravitas Bloop Fish | 609,558 |
| Giant Gravitas Leviathan | 587,228 |
| Giant Gravitas Livyatan | 507,644 |
| Giant Gravitas Olympian Devil | 490,914 |
| Giant Requies Colossus Reef Titan | 460,141 |
| Giant Gravitas Photic Terrosunder | 453,212 |
| Giant Gravitas Humpback Whale | 451,505 |
| Giant Gravitas Ancient Goldwraith | 450,683 |
| Giant Gravitas Leviathan (duplicate) | 440,035 |
| Giant Gravitas Profane Leviathan | 425,623 |
Note: The duplicate Leviathan earns less than the first copy because of the duplicate penalty. Aim for unique species wherever you can to avoid losing money to that reduction.
Avoid the duplicate penalty
Placing more than one copy of the same species triggers a Duplicate: -25% penalty on the extra copies, cutting both credits and XP. In the aquarium menu, duplicate slots are marked with a red label so you can spot them. Replace repeated species with a different high-value fish whenever possible, since a unique fish at full rate almost always beats a second copy running at a 25% loss.
Stack weight and size buffs before you place a fish
Because weight and size feed straight into the profit formula, the biggest gains come from catching each fish while your buffs are active. Layer these effects in order for the heaviest possible catch.
Tip: The +infinite Max Kg from the Shell of Depth matters for the largest catches, since some fish weigh millions of kilograms and would otherwise exceed a rod’s limit.
Keep food buffs running for the extra multiplier
Food buffs are what carried the example tank from 3.1M to 6.2M C$ per hour. Buy fish food from inside the aquarium menu and consume it to apply a temporary multiplier across your whole tank. Reapply it before long AFK sessions so your passive rate stays at its peak.
| Food item | Price |
|---|---|
| Splash Snacks | 1,500 C$ |
| Fish Chow | 4,500 C$ |
Catch Leviathans with the Great Dream Waker harpoon
Several of the top earners in the lineup are Leviathan-class fish, and the Great Dream Waker harpoon gun is built to land them. Its Hunt Focus grants +30 against Leviathans, and its 35,000 Max Kg ceiling handles their weight. Use it during high-density server events such as Ghastly Tide and Mega Mayhem, where the strongest catches appear.
| Great Dream Waker stat | Value |
|---|---|
| Power | 32 (+10) |
| Range | 128 studs |
| Reload | 2.50s |
| Velocity | 30/ps (-5) |
| Resilience | -10% (+10) |
| Accuracy | 30% |
| Max Kg | 35,000 |
| Hunt Focus | Leviathan (+30) |
How to confirm the farm is working
Open the Personal Aquarium menu and check the Hourly Profit readout at the top. When you apply a food buff, the number climbs in real time and a green overlay shows the exact gain, such as +$129,934. If your rate is stuck lower than expected, look for red duplicate labels, confirm your food buffs are still active, and verify that heavy giant fish are filling every slot rather than lighter placeholders.
Set realistic expectations for the ceiling. The largest 100M-per-hour setups were removed through rebalancing, so a standard optimized tank now lands in the 5–10 million range, with 15 million or more reserved for special events and rare gear. The 6.2 million rate here sits right in that optimized band, and once the tank is built it keeps paying out passively, online or off.
