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Squirrel's Pick Squirrel's PickThe best game on this page. If you only try one, try this. Budget Pick Budget PickThe best game here for the least money.
Creature CollectorIdlerFishing
Cozy CozyLow-stress and wholesome — a game to unwind with.
$2.99 ~47.1 hr median no co-op complexity: light 92.3% of 8k
The Squirrel's verdictCard packs and idle income drive Chillquarium's loop: buy a pack, unlock fish, wait for them to grow, sell for currency to buy more packs. At $2.99 and a median 47 hours of playtime, it suits players who want a long-haul fish-collection grind rather than the hands-on aquascaping and short fixed campaign Aquarium Designer offered.
Not for you if you want direct control over tank layout and fish placement rather than passive growth and RNG card pulls.
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Tiny Aquarium: Social Fishkeeping
PCMacLinux
CollectathonCreature CollectorIdler
$7.49 ~43.5 hr median no co-op complexity: light 96.1% of 4k
The Squirrel's verdictBreeding, hatching, fishing, and trading fish across multiple tanks form Tiny Aquarium's ongoing progression, replacing the short fixed campaign found in Aquarium Designer. Released in 2025 with an Overwhelmingly Positive rating and a median playtime of 43.5 hours, it suits players who wanted more content and social trading after finishing a story-driven aquarium game.
Not for you if you want species-specific realistic fish behavior rather than a cozy loop of feeding, cleaning, breeding, and trading.
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UnderwaterCreature CollectorCute
Cozy CozyLow-stress and wholesome — a game to unwind with. Strong Mods Strong ModsA deep, active modding scene extends it past its base content.
$24.99 ~69 hr median no co-op complexity: moderate 95.3% of 4k
The Squirrel's verdictBoth let you build and stock aquarium tanks with fish and decor. Megaquarium adds tycoon-style management: guest needs, staff, unlockable species offers, and a business layer Aquarium Designer never had. Median playtime sits at 69 hours versus Aquarium Designer's short campaign, for players who want the tank-building loop with actual progression to sink time into.
Not for you if you want pure aquascaping without guest management, staff hiring, or business-sim mechanics layered on top.
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Closest Match Closest MatchThe most similar game to the anchor, by what players say. Hidden Gem Hidden GemLoved by the players who found it, but still under the radar.
Immersive SimCreature CollectorIdler
$24.99 ~19.3 hr median no co-op complexity: light 93.3% of 624
The Squirrel's verdictFish Game shares Aquarium Designer's core loop of building tanks and managing species behavior, but trades the short structured campaign for an open-ended XP system: you unlock fish and equipment by playing, with a median playtime of 19.3 hours against Aquarium Designer's abrupt few-hour finish. Suits players who want more time in the tank-building sandbox and don't mind grinding for unlocks.
Not for you if you want story missions rather than a grind-to-unlock progression, or dislike a gameplay loop that's mostly feeding fish and changing water between building sessions.
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Hidden Gem Hidden GemLoved by the players who found it, but still under the radar.
Creature CollectorIdlerFishing
Cozy CozyLow-stress and wholesome — a game to unwind with.
$5.99 ~23.7 hr median no co-op complexity: light 90.7% of 551
The Squirrel's verdictAn idle collector loop with achievements to chase, Joyquarium trades Aquarium Designer's structured campaign pacing for passive fish growth and currency accumulation. Median playtime reaches 23.7 hours against Aquarium Designer's abrupt few-hour finish. Reviewers note it closely resembles Chillquarium in design, with simpler decorating options and snap-to-ground placement throughout.
Not for you if you want distinct fish behavior by species, meaningful decorating depth, or a game with a clear structural difference from Chillquarium.
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EducationJob SimulatorCreature Collector
Cozy CozyLow-stress and wholesome — a game to unwind with.
$6.39 ~17.5 hr median no co-op complexity: light 83.9% of 1k
The Squirrel's verdictSame core loop: stock tanks, place decor, manage fish species in a shop/collection framework. Aquarist trades Aquarium Designer's short campaign for a longer tutorial-into-open-play structure with a median 17.5 hours logged, more content but rougher edges—fiddly item placement, shallow fish-care simulation, and reported bugs.
Not for you if you want precise item placement or accurate fish behavior and husbandry detail rather than a longer but buggier decorating loop.
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CuteLife SimNature
Cozy CozyLow-stress and wholesome — a game to unwind with.
$19.99 ~5.9 hr median no co-op complexity: light 84.5% of 400
The Squirrel's verdictFishery shares Aquarium Designer's stocking-and-decorating core and a similar median playtime of 5.9 hours. It includes water chemistry controls and CO2 management Aquarium Designer never modeled, but a later update removed much of that simulation depth according to multiple reviews, leaving the game closer to a tank-decorating sandbox than the layered sim older reviews describe.
Not for you if you're counting on deep gas and plumbing simulation; multiple reviews confirm those mechanics were stripped in a post-2021 update.
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Life SimImmersive SimEducation
$14.99 ~2.5 hr median no co-op complexity: moderate 42.3% of 220
The Squirrel's verdictWater chemistry simulation is Biotope's entire focus: pH, nitrogen cycle, and husbandry management replace the campaign structure and aquascaping objectives Aquarium Designer used. With no story mode and a median playtime of 2.5 hours, it suits players who wanted Aquarium Designer's realism angle pushed further into genuine fishkeeping simulation rather than scored decorating tasks.
Not for you if you want a structured campaign, or a project with confirmed post-2019 developer updates.