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Planet Zoo 2 aquarium guide: tank size, shoals and tank mates

Aquarium only, or aquarium and exhibit

The Zoopedia lists 21 species for the aquarium alone and 16 for both the aquarium and an exhibit. All 16 dual-listed species are shoaling ray-finned fish, and their first-fish deep water figure is either 50 m² or 100 m². Every shark and ray, plus the turtle and the manatee, is aquarium-only. For species kept only in exhibits, see the exhibit animals list.

Deep water space for every aquarium species

Deep water is the area type every aquarium species lists. The table runs from the smallest first-animal figure to the largest; the full-group column assumes the largest group the Zoopedia allows.

The figures bunch up in the middle. Fourteen species start at exactly 50 m² and another seven at 100 m², so 21 of the 37 share one of two values, and the median first-animal figure is 50 m². From 200 m² up, the list thins out to six species, three of them sharks or rays, topped by the Great Hammerhead.

The West Indian Manatee is the exception to the deep water pattern. It needs only 20 m² of deep water for the first animal but 150 m² of aquatic space, with 25 m² more per extra manatee. No other aquarium species lists aquatic space at all.

Shoaling species

The Zoopedia marks 21 species as shoaling, and every one is a ray-finned fish kept in the aquarium. That covers all 16 dual-listed fish plus five aquarium-only ones: the Golden Trevally, Indian Ocean Oriental Sweetlips, Longfin Batfish, Pacific Bluefin Tuna and Pacific Sardine. No shark, ray, turtle or manatee is marked as shoaling.

Their numbers follow a tight pattern. Every shoaling species has a minimum group of 1, and the maximum is five for 14 of them, four for six and three for one, the Pacific Sardine. Each one also adds exactly 30% of its first-fish figure for every extra fish: 15 m² after 50 m², 30 m² after 100 m², and 60 m² after 200 m² for the Pacific Bluefin Tuna, the largest shoaling species by deep water.

The largest aquarium groups

Big groups in the aquarium belong to species that are not marked as shoaling. These seven species allow ten or more animals.

The Javanese Cownose Ray is the only aquarium species with a minimum group above two: you start with five rays and can go up to 40. The Sand Tiger Shark is the only one whose minimum is exactly two. Every other aquarium species can be kept singly.

Tank mates: four groups that don't mix

Following every listed pairing from species to species splits the aquarium into separate groups. No species in one group lists any species in another, so a tank should draw from a single group. The last column is the temperature band all members of the group accept together.

Large marine group

This group holds the sharks and rays (all but the hammerhead), the Hawksbill Turtle and the non-shoaling fish. Thirteen of its 14 species are each listed as compatible with all twelve of the others. The Ocean Sunfish is the exception: it pairs with only seven of them and is not listed with the Blacktip Reef Shark, Hawksbill Turtle, Javanese Cownose Ray, Ocellated Eagle Ray, Red Lionfish and Sand Tiger Shark.

All 38 thriving pairings in the aquarium sit in this group, and each one involves one of four species: the Humphead Wrasse, Indo-Pacific Leopard Shark, Javanese Cownose Ray and Ocellated Eagle Ray. Each of the four thrives with 11 others. If you want thriving pairs in a tank, build it around one of them.

Shoaling marine group

These 13 shoaling fish are all compatible with each other, but every pairing is neutral. Together they accept 24 to 26 °C. Leave out the Pacific Bluefin Tuna and Pacific Sardine, whose ranges stop at 26 °C, and the band for the remaining 11 widens to 24 to 28 °C.

Freshwater groups

The Blunthead Cichlid, Boeseman's Rainbowfish, Clown Loach and Giant Gourami form a group of four that all list lakes and rivers as their biome, though they come from Africa, Asia and Oceania. All four together accept only 25 to 27 °C. The Koi and Common Rudd make a separate pair at 18 to 24 °C, below the band of every marine group.

Temperature inside a mixed tank

Aquarium ranges are narrow to begin with, so mixing trims them to very little. Of the 170 aquarium pairings, 77 share exactly 4 °C, the most common width. The tightest fit is the Ocean Sunfish: its 10 to 25 °C range meets the 24 °C floor of the Dolphinfish, Giant Grouper and Indo-Pacific Leopard Shark and leaves a shared band of just 24 to 25 °C. Its other partners start lower, at 22 or 23 °C, and give a little more room.

The habitat planner works out the shared range and total deep water for any set of species and counts, which helps once a tank holds more than two species.

Species with no tank mates

Four aquarium species have no listed partner: the African Tigerfish, Brown Trout, Great Hammerhead and West Indian Manatee. That leaves the hammerhead, which also has the largest first-animal deep water figure, needing a tank of its own. The tigerfish and trout are shoaling fish that list lakes and rivers, yet neither appears in the freshwater groups above.

Every pairing is listed on what animals go together, and any two species can be checked side by side in the animal comparison. The animal list filters the full roster by enclosure type.

Aquarium data comes from the official Zoopedia (checked 2026-10-14). The groupings, bands and totals here are worked out on this site, and the method page explains how the data is collected.