Breeding fish

The player can breed fish at their workshop by placing at least two fish of the same species and rarity within the same fish tank and feeding them adequately over time. On the day that the two breeding fish reproduce, the resulting offspring will appear within the tank as a fully-grown fish of the same species and quality as the parents.

Please note that Ack does not feed or otherwise take care of the player's fish as part of his services as a helper.

Fish tanks

 * Not to be confused with Portia Museum's Aquarium

Fish tanks can be placed in the player's house and yard. To put fish into a tank, the player must hold the fish in their active toolbar slot, face the tank, and press the interaction button. This action puts a single fish in.

All of the fish in a tank will consume a set amount of food and, if possible, reproduce once per day at an hour randomly selected when the tank itself is placed on the ground. In the table below, Adult Capacity denotes the maximum number of fish the player may place into the given tank, whereas Max Capacity denotes the maximum number of fish that may exist within the tank before breeding is halted. The player may remove fish at any time, but will not be able to add additional fish into the tank until the number falls below Adult Capacity.

To remove fish, the tank must be interacted with while not holding a fish or other non-tool item. Fish are removed one at a time, starting with the fish that was introduced to the tank most recently (regardless of whether the fish was manually added or born in the tank), and ending with the fish that was added to the tank first. For example, if one Golden Salmon, one Catfish, another Golden Salmon, and a Wise Fish were added to a tank, then a third Golden Salmon was born, then the fish would be removed in the following order: newborn Golden Salmon, Wise Fish, second Golden Salmon, Catfish, then the first Golden Salmon.

Feeding & Hunger
The player must adequately feed the fish in the tank in order to make them breed. However, if not fed, fish do not die and are simply a cosmetic addition to the House.

To feed fish in a fish tank, the player must be holding the appropriate item in their toolbar. Each item usable as fish food will provide a specific amount of nourishment (see HP Restored in the table above). Once a day your fish will lose HP (see Daily HP Loss in the breeding section's table). The exact hour your fish lose HP is set randomly when the fish tank is placed. A fish will become hungry once its HP falls to half. If any fish in a tank is hungry, the following icon will be shown above the tank when the player approaches:


 * A fish will not eat if they are above 150% HP.
 * All food is eaten (or wasted) immediately and can boost a fish's HP above 150%, thus you can feed your fish in single large doses and not feed them daily.
 * Food (HP gain) is distributed evenly among all fish that will eat (those below 150% HP).
 * Days spent hungry will not count towards a fish's Days to Breed requirement (see the breeding section's table). However, the number of previous days spent adequately fed will not be lost and progress will resume once the Player provides enough food to alleviate the hunger.
 * Removing a fish then putting it back into a tank will reset its HP back to 100% HP, and also resets Days to Breed.
 * Food cannot be added when the tank has no room left for new fish, so at least one fish must be removed first.

Example Feeding Calculations
Single King Fish:


 * A Single King fish is placed in a new tank (100% or 300 HP).
 * 10 Bug Eggs are fed to the tank (600 HP worth).
 * King Fish HP = 300% (300 Fish HP + 600 Food HP = 900 HP).
 * It will now take ~13 days to reach Hungry status (-60 HP/Day).

Max Stack Loading a Tank:


 * A Single King fish is placed in a new tank (100% HP).
 * 999 Dough is fed. That fish is now at 6,760% HP.
 * A second King fish is added to the tank.
 * 999 Dough is fed. The first fish will not eat (since its above 150%HP ) so now both fish are at 6,760% HP.
 * Repeat for all new fish to get 300+ days of fed status.

Multiple Fish:


 * Three Banner Fish are added to the tank (100 HP each at 100%).
 * A single Dough is fed to them (20 HP gain).
 * All three fish are at 107% (rounded).
 * When dividing food the total HP that would be gained is divided, not the number of individual pieces of food. Thus 20 HP / 3 fish = ~107 HP each instead of 1 fish with 120HP and Two with 100HP.

Daily Needs of a Random Assortment:


 * A mixed fish tank makes it very hard to calculate a precise per-day feeding amount. The easy thing to do is overfeed by taking the per-day HP loss of your "hungriest" fish and simply feeding the whole tank at that rate:
 * Given a tank with the following fish: 2 Banner, 2 Bubble, 1 Goliath, 1 Emperor Gladiator, 2 King Fish.
 * In this case you would need 36 Dough a day to guarantee fed fish because of the Goliath: 90 HP/day * 8 Fish = -720 HP loss day / 20 = 36 Dough.
 * To get a precise (less wasteful number) your Goliath would lose HP until your less hungry fish reach 150% HP and stop eating, then the overflow for that day would make up the loss on your Goliath.
 * That said in this case there is only 1 Goliath, thus is not a breeder so you can underfeed him and only care about the hungriest breeding fish (the king fish) and feed only 24 Dough/Day. You may get a "Hungry" icon sometimes but it won't affect breeding.

Breeding
Breeding will occur between a pair of fish in the tank if all of these conditions are met at the randomly selected hour they are checked:
 * Both fish are of the same Species and Rarity.
 * The tank is not full (see Max Capacity in the tanks section's table).
 * Neither fish is currently hungry.
 * Both fish have spent the required amount of days (see Days to Breed in the table below) in the tank while not hungry.

The number of days left until they breed is decremented before the Daily HP Loss is applied, so becoming hungry right after the check is not a problem. As long as you feed them out of that status before the next day's check time the fish will breed.

Trivia

 * Breeding fish is one of the commonly player-recommended strategies for making Gols efficiently, and is an option that becomes available fairly early in the game. The fishing tourney also provides a great opportunity to obtain even rare fish to breed with early on.
 * It is possible to make more Gols via breeding fish on the PC version of, as the has a limit of approximately 50 items that can be placed but PC players are only limited by the amount of physical space their yard allows.
 * During some Early Access versions, fish died if not fed. This feature was removed before the official release of the game.