Evolve fish and build aquarium income
Put a catch in the aquarium, EVOLVE it, and it starts paying cash every second. Growth is slower offline - the game tells you fish grow 20% faster while online - so the aquarium upgrade cost only makes sense once a full rack of pets is paying out.
Catching is the fast half of Harpoon a Fish. The aquarium is the slow half, and it is where a patient player overtakes a busy one.
What the aquarium actually does
The official description gives the loop in one line: put caught fish in your aquarium and grow your new pet. Once a catch is in the tank it stops being a one-off payout and starts producing income.
- Pets pay cash every second. The HUD shows a per-second figure for the tank, with percentage bonuses beside it.
- They grow. Growth is a timer, and the timer runs on real time, not on your session.
- Offline still counts, but slower. The game says it plainly on screen: fish grow 20% faster while ONLINE!
That last line is the whole economics of the page. The aquarium is not a save-it-and-forget-it machine; it is a machine that runs best while you are playing, which is why leaving the game open on the island is a real strategy.
EVOLVE, in practice
EVOLVE is the game's word for pushing a pet up a tier. Each step makes the pet a bigger and rarer sea monster, and bigger pets pay more per second. Because evolution is applied to the pets you already own, the order you evolve in matters:
- Fill the rack first. A tank of basic pets out-earns one evolved pet plus empty slots.
- Then evolve the pet you can replace. Evolution competes with filling a slot, so only evolve when the next catch would not be an upgrade.
- Then catch the tier you cannot buy. The aquarium's real ceiling is what your depth lets you bring home - see depth layers.
Aquarium upgrades: when the price is worth it
The upgrade panel shows levels, for example a step from one level to the next with a cash price attached. Larger upgrades cost real money - tens of thousands of cash once the tank matures.
Two rules of thumb keep those purchases honest:
- Upgrade when the tank is full and every pet is paying. An upgrade on a half-empty tank buys capacity you are not using.
- Do not upgrade the tank and the Mukbang table in the same dive cycle. One raises income, the other raises reach; buying both at once leaves you with neither paid off.
Where the cash goes next
The aquarium pays, the catches pay, and both feed the same three purchases:
| Purchase | What it buys you |
|---|---|
| Mukbang table levels | Weight, and therefore depth |
| Aquarium upgrades | More pet slots and higher per-second income |
| Equip slots | More harpoons per shot, for contested catches |
If you find yourself holding cash, the tie-breaker is depth: the next band down pays more than the next aquarium level does, and it also advances your index. The money and progression page puts that order into numbers.
A cheap aquarium routine
- Land one good pet per session, at the deepest band you can reach.
- Bank the rest of the bag as cash.
- Evolve when a slot is empty, not when the tank is full.
- Claim your playtime rewards before you log off - the XP and potions feed the run that follows.
