Marine clean-up crew: animals that keep aquariums clean

Aggressive algae growth (due to prolonged light exposure) and accumulation of detritus (non-living organic matter such as leftover feed and excrement) are common problems faced by any aquarium. But harsh chemicals and aggressive cleaning may disrupt the delicate ecosystem of its habitats.

The solution? Employ the help of sea dwellers which naturally clean up the sea – the marine ‘clean-up crew’.

Decorator Urchins

Decorator Urchin

Decorator Urchins (also known as Collector Urchins) are named for their habit of picking up rubble and debris, and camouflaging themselves with their newfound treasures. Quirky habit aside, these urchins are among the best algae busters of the sea, scraping them off rocks and other hard surfaces with their teeth.

Decorator Urchin

Decorator urchins are extremely effective at removing algae from rocks. So much so that we often see clean, algae-free trails on rocks in the habitats. A sign that these urchins have been doing their job.

——-– Jason Lim, Senior Aquarist at S.E.A. Aquarium who captured the above images of our Decorator Urchins.


foxface rabbitfish

When it comes to appetite for algae, few fish can compete with the Rabbitfish which are frequently seen pecking at algae-ridden rocks. While they may appear cute and harmless, these algae eaters have sharp, venomous dorsal spines to defend themselves against predators.


Surgeonfish feed primarily on algae, making them an ideal choice to rid a habitat of unwanted algae growth. Among them, the Yellow Tang (a member of the Surgeonfish family) is one of the most effective grazers. Their extended rostrum makes them particularly good at picking off algae out of rock crevices where most other Surgeonfish can’t reach.

Yellow Tangs pecking at algae on the rocks

Cleaner Shrimps

Image source

These shrimps scavenge for leftover food, hence preventing decomposing food from raising nitrate levels in the water. At the same time, they pick parasites off fish and are used to control saltwater ich (white spot disease in fish). Some of the most popular cleaner shrimps are the Pacific Cleaner Shrimp and the Scarlet Cleaner Shrimp (also called the Fire Shrimp).

Cleaner Wrasses

Instead of chowing down algae, Cleaner Wrasses form a symbiotic relationship with other species by removing (and eating) parasites found on their body, such as their mouth and gills. The bigger fish recognise them by their lateral stripe along the length of their bodies, and by their dance-like motion in which they move their rear up and down.

Cleaner Wrasses share the same habitat as Moral Eels at S.E.A. Aquarium. They are often seen cleaning the mouths of these eels.

If you have a saltwater aquarium at home, rabbitfish and surgeonfish are pretty hardy options to help you keep algae under control. But always consult a professional before you purchase any fish. If you don’t have an aquarium at home, you can always visit the S.E.A. Aquarium to marvel at marine wonders, including these marine clean-up crew.

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