# Algae & cleaning

_Why the glass gets cloudy, and what slows it down._

## How algae builds up

In a bare aquarium, algae starts to grow 4 hours after the last clean, and the glass gets gradually dirtier until you look after it.

## Plants and decorations buy time

Every plant and decoration pushes that moment back a little, and plants do the most. The total is capped at 4 times the usual time, so decorations never make cleaning unnecessary. Each item in the [decorations catalogue](https://fishies.lol/wiki/decorations) shows how long it keeps algae away on its own. A filter adds to that on top of the cap: a better filter keeps the glass clear for longer, up to twice as long, but it never cleans it for you.

## Busy aquariums get dirty sooner

The more fish you keep, the faster the glass clouds over. Eggs count too.

- 6 fish or more: the glass stays clear for 85% of the usual time.
- 12 fish or more: 70% of the usual time.
- 18 fish or more: 60% of the usual time.

## A fish that grazes the glass

A grown, fed [Bristlenose Pleco](https://fishies.lol/wiki/species/Bristlenose_Pleco) grazes the glass, so algae builds up 1.5 times more slowly. It never scrubs the glass for you and never earns the cleaning reward, and a hungry pleco stops grazing until it's fed. Each aquarium can keep one.

## Scrubbing the glass

Choose Clean and scrub with the sponge. Cleaning glass that has had time to get dirty pays a small reward, while scrubbing glass that's already clear pays nothing.

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In the game: https://fishies.lol/wiki/mechanics/cleaning · Fishies 0.8.3

This page is generated. Its text lives in [`locales/en-GB.json`](../../../locales/en-GB.json) under `wiki.topics.cleaning`; correct it there.