Aquarium

The Aquarium, run by Charles in South Pawville, allows the player to display fish they catch.
== Fish Storage and Display ==
The player can use the Aquarium to store fish after the Repair the Aquarium quest. Initially, it can hold 10 fish in each of its two tanks: the Sea Fish Tank and the River Fish Tank. This number rises to 20 with the Find Driftwood (Dogz) / A Lava Stone (Catz) quest, and then 30 with the Find the New Breed Rainbow Fish (Dogz) / Golden Angler Fish (Catz) quest. Fish caught at certain piers are Sea Fish, while Fish caught at others are River Fish, and no fish can be caught at both sea piers and river piers.
Sea Piers
* South Pawville
* Dolphin Coast (Both)
* Jade Fields (Sea)
* Monolith Isle
* Polar Fields (Sea)
River Piers
* Zoo
* Jade Fields (River)
* Lappy Lake (Both)
* Whisker Woods
* Tail Heights
* Polar Fields (Pond)
* Gongoro Peak
When the player stores fish in a tank, they can see them swim across the tank. The player can display whichever configuration of fish they find most interesting and appealing. This article highlights some fish that are rare in some specific metrics, and thus may be of interest for display: maximum size, catching difficulty, rarity, distinctive swimming, and distinctive appearance. These categories often overlap: fish like the New Breed Rainbow Fish and Golden Sunfish perform well in most or all of them. For information on where and how to best catch these fish, see the Fishing article for pier-by-pier analysis, or the Fish article for a simpler list of locations.
When fish are withdrawn from a tank, they are permanently lost and not returned to the player's inventory. If one is not sure how they want to set up their tank, they can consider saving before modifying the Aquarium, putting fish in and out to find out their preferred display, and resetting the game without saving to undo these permanent deletions.
== Sea Fish Tank ==
The Sea Fish Tank generally has more large, vibrant, rare fish available.
=== Size ===
The following lengths are derived from the Fish article and in centimeters. The maximum values are confirmed to be possible, but the range may be incomplete, and the lower values may be speculative.
# Golden Swordfish (400- 457)
# Golden Sunfish (400 - 450)
# New Breed Rainbow Fish (300 - 400)
# Sunfish (300 - 400)
# Swordfish (300 - 400)
# Tuna (188-320)
# Napoleon Fish (162-203)
# Golden Salmon (100-200)
# Ray (100-200)
# Golden Angler Fish (100-199)
# Hairtail (180)
=== Catching Difficulty ===
The following fish have the extra-large eye icon when reeled, making them tie for the hardest fish in the game to catch. 
Golden Swordfish, Golden Sunfish, New Breed Rainbow Fish
These fish sometimes have the icon. For these species, the fish must be sufficiently long to have the icon. The first number is the smallest fish confirmed to have it, and the second number is a speculative range.
Sometimes: Sunfish (357; 350+), Tuna (242; 200+), Napoleon Fish (203; 200+), Ray (200; 200)
=== Rarity ===
These fish have the lowest average rarity or setup-adjusted rarity in their most common location. For more information on these types of rarity, see the Fishing article.
# Golden Swordfish (4.09%)
# Golden Sunfish (4.17%)
# Angler Fish (4.3%)
# Golden Angler Fish (4.33%)
# Napoleon Fish (4.38%)
# Golden Salmon (4.47%)
# Tuna (4.5%)
# New Breed Rainbow Fish (4.69%)
# Hairtail (5.6%)
# Ray (6.18%)
=== Swimming ===
These fish swim with a unique animation:
Octopus, Squid, Sole, Tuna
The Sole, notably, does not move. Moving the camera can help to spot it if it spawns outside the default visual range.
=== Appearance ===
The golden fish are the Golden Swordfish, Sunfish, Angler Fish, and Salmon.
Other fish with distinctive appearance are the New Breed Rainbow Fish, Swordfish, Hairtail, Octopus, Squid, and Ray.
== River Fish Tank ==
The River Fish Tank generally has fewer large, vibrant, rare fish available.
=== Size ===
The following lengths are derived from the Fish article and in centimeters. The maximum values are confirmed to be possible, but the range may be incomplete, and the lower values may be speculative. The Golden Arapaima, by current knowledge, can reach the largest length of any fish in the game. The Golden Carp is strongly speculated to have a maximum length of at least 100cm, but this is currently unconfirmed.
# Golden Arapaima (400- 480)
# Arapaima (300-450)
# Gar (100-184)
# Marbled Lungfish (140-180)
# Bighead Carp (80-180)
# Ito (128-165)
# Ancient Fish (120-160)
# Grass Carp (80-120)
# Arowana (70-120)
# Eel (60-110)
# Carp (60-100)
# Rainbow Trout (40-100)
=== Catching Difficulty ===
The following fish have the extra-large eye icon when reeled, making them tie for the hardest fish in the game to catch. 
Golden Arapaima, Arapaima
=== Rarity ===
These fish have the lowest average rarity or setup-adjusted rarity in their most common location. By this metric, the Golden Carp is the rarest fish in the game. For more information on these types of rarity, see the Fishing article. The Golden Killifish is italicized because it's small size makes it very difficult to see in the Aquarium.
# Golden Carp (3.13%)
# Gar (3.42%)
# Golden Killifish (3.46%)
# Ito (3.51%)
# Ancient Fish (3.78%)
# Bighead Carp (4.47%)
# Golden Arapaima (5.33%)
# Arapaima (5.38%)
# Minnow (7.36%)
# Arowana (8.38%)
=== Swimming ===
These fish swim with a unique animation: Starry Flounder
The Starry Flounder, notably, does not move. Moving the camera can help to spot it if it spawns outside the default visual range.
=== Appearance ===
The golden fish are the Golden Arapaima, Golden Carp, and Golden Killifish.
Other fish with distinctive appearance are the Gar, Snakehead, Marbled Lungfish, Arowana, Arapaima, Eel, and Ancient Fish.
The Golden Killifish and Killifish have a "distinctive" appearance in that both are tremendously difficult, though not impossible, to spot given their tiny size. This is especially true if other fish are present in the aquarium, or if they swim near the brighter areas of the tank. Using the Zoom function of the Aquarium camera can help to find them. The player may consider keeping these fish in the inventory for display, instead of taking up limited Aquarium spaces, especially since they cannot withdraw the fish from the Aquarium without losing them entirely.
== Trivia ==
On the Wii version, fish still swim in the tank when the game is paused with the Home menu.