Comparison

marimo vs Medaka Aquarium Breeder

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

marimo

A virtual pet simulation where you nurture a Marimo, a unique aquatic plant from Hokkaido. The core gameplay involves changing its water to help it grow. You can then share your Marimo's progress with friends.

Highlights
  • Virtual Marimo pet
  • Water changing gameplay
  • Marimo growth simulation
  • Share progress on Twitter
  • Hokkaido souvenir theme
Features
Read full description

Marimo-chan is an application to grow the "Marimo" on the iPhone. Inhabit Lake Akan in Hokkaido, can be observed / breeding on the iPhone the "Marimo" very popular as a souvenir of Hokkaido. Is a very simple system. Basically all you have to do change water. When Marimo grow large then Let's boast to your friends on twitter

About

Medaka Aquarium Breeder

Raise and breed killifish in a relaxing aquarium simulation. Manage water quality, feed your fish, and sell them to upgrade your tank. Discover new species and create a beautiful underwater world.

Highlights
  • Manage aquarium water quality and temperature
  • Feed and grow killifish
  • Sell fish to earn money
  • Breed new killifish species
  • Customize aquarium with equipment and layouts
  • Offline play available
Features
Read full description

Medaka Aquarium Breeder is an idle breeding game where you become a medaka breeder, manage your aquarium, and raise your own medaka fish. Adjust the water temperature and quality, feed your medaka, and watch them grow over time. Even while the app is closed, your medaka continue to grow little by little. Sell the medaka you raise to earn money, buy aquarium equipment and layout items, and create your own relaxing aquarium. A major update has expanded the breeding and collection experience. Main features added in the update: - View medaka relationships and breeding routes with the genetic map - Use Breed Points to unlock hints for undiscovered medaka and analysis for discovered medaka - Expanded breeding patterns make it possible to discover more medaka varieties - Seasonal Shop where you can obtain medaka inspired by spring, summer, autumn, and winter - Expanded encyclopedia and genetic map with more detailed information about discovered medaka - Updated Tips to make new features and breeding advice easier to understand How to play: - Manage water temperature and quality, and feed your medaka as they grow. - Feeding and cleaning take only a short time, making it easy to care for your aquarium during spare moments. - Sell raised medaka to earn money, then buy aquarium equipment and layout items. - Pair male and female medaka to produce offspring that inherit traits from their parents. - Use the genetic map and encyclopedia to search for medaka you have not discovered yet. - Check in-game Tips anytime to learn about raising medaka and using each feature. Features: - Idle growth system where medaka continue to grow while you are away - Aquarium layout customization with equipment, sand, aquatic plants, stones, and more - Collection gameplay where breeding can lead to new medaka varieties - Encyclopedia to review discovered medaka - Genetic map to check parent-child relationships and breeding clues - Seasonal Shop where different medaka appear depending on the season - A calm aquarium atmosphere with water sounds and music The medaka available in the shop are only part of what you can discover. Some medaka can only be created through breeding, and others are connected to the seasons. Think about parent combinations, unlock hints with Breed Points, and work toward completing your encyclopedia. Recommended for players who: - Enjoy raising games that can be played little by little - Like aquariums and relaxing water-themed experiences - Enjoy caring for virtual pets - Like discovering new varieties through breeding or pairing systems - Want to steadily complete an encyclopedia or collection - Want a calm game to enjoy during breaks or quiet moments Raise medaka, breed new varieties, expand your encyclopedia, and create your own aquarium.

Screenshots

marimo4 screens
Medaka Aquarium Breeder4 screens

Verdict

The call

The clearest difference is ads: marimo at none against Medaka Aquarium Breeder's shown. marimo also leads on monetization model (free vs ad-supported) and iOS requirement (9.0 vs 13.3). Medaka Aquarium Breeder's advantage is update cadence (every 11 days vs every 4 months). On price, review sentiment, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

marimo ships an update every 4 months, Medaka Aquarium Breeder every 11 days. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

Scorecard4 real differences · 6 level
marimo versus Medaka Aquarium Breeder: the parameters behind the verdict, then further details
ParametermarimoMedaka Aquarium Breeder
PriceFreeFree
Rating—4.3 (3 ratings) — better
Positive reviews98.0% of reviews100.0% of reviews — better
Number of ratings—3 — better
Update frequencyEvery 4 monthsEvery 11 days — better
AdsNo — betterYes
In-app purchasesNoNo
MonetizationFree — betterAd-supported
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS9.0 — better13.3
Further details — not scored
Size31 MB244 MB
Age rating4+4+
DeveloperHANA-DA HiromitsuYuki Naruse

Customer experience

marimo

Written reviews50 reviews
Positive98.0%
Neutral0.0%
Negative2.0%

Medaka Aquarium Breeder

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews4 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

marimo

No in-app purchases

None

Medaka Aquarium Breeder

No in-app purchases

Questions

Is marimo free?
marimo is free to download, with no in-app purchases.
Is Medaka Aquarium Breeder free?
Medaka Aquarium Breeder is free to download, with no in-app purchases.
Do marimo or Medaka Aquarium Breeder have ads?
Medaka Aquarium Breeder shows ads; marimo does not.
Which is updated more often, marimo or Medaka Aquarium Breeder?
marimo ships an update every 4 months, and Medaka Aquarium Breeder every 11 days. Most recently, marimo was updated on November 1, 2026 and Medaka Aquarium Breeder on November 3, 2026.

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