My favourite algae eating (herbivorous) marine fish

  • I thought I would put something together for those new to the hobby or those not familiar with which fish are good herbivores to help control the various nuisance algae’s that can grow and become a nuisance in our home aquariums. Yes there are many various forms of chemical and other filtrations suitable for controlling algae growth, but I think it is very important not to overlook the importance and value of herbivorous fish and invertebrates for your aquarium. There are also many different fish and I’m sure some will prefer a different fish over another one based on their experience, you also need to bear in mind that this is my list from my own personal experience over my years of fish keeping and may differ from others opinions and preferences, you should always research any fish before you buy it to familiarise yourself with its requirements and it’s compatibility with the fish already resident within your aquarium and also check if they are reef safe (some fish eat corals and hermit crabs and shrimps etc.)

    Lawnmower Blenny – Salarias fasciatus

    Maximum Size fish grows to: 13 to 15 cm’s. Will be ok in a 2ft tank.
    My Info: Some people think they are ugly, some think they are cute, I loved my little guy, he used to park himself in the strangest of places, mostly on top of my Squamosa clam though (who never seemed to mind), they will spend their time making short swims up into the water column, scraping bits of micro algae off the glass and also off the rocks, before plonking themselves down somewhere and looking like they are keeping an eye on you on the other side of the glass.


    Yellow Foxface Rabbitfish –Siganus unimaculatus

    Maximum Size fish grows to: about 18 cm’s so you need a biggish tank, minimum 4ft I would say.
    My Info: One of my favourite fish, lovely colouring and becomes very friendly, will take food from your fingers once it settles in and gets to know you, spends a lot of it’s time browsing the tank for algae on the rocks and also on the glass, seems to prefer the shorter variations of algae, if you have long green hair algae then pull off as much of the long stuff as you can and the foxface should hopefully eat the shorter bits left behind. Spends most of its time swimming in the water column but like to sleep against or behind something at night, also has stress and sleep patterns that look like camouflage. Be very careful when handling this fish or putting your hands in the tank, his dorsal fins (the ones along the top of the fish) are highly venomous and will cause severe pain if you get stung by them. Enjoys being fed Nori or Algae flakes.


    Regal Tang - Paracanthurus hepatus

    Maximum Size fish grows to: 30 cm’s but generally smaller in home aquaria. Bare minimum 4ft tank needed, although they really enjoy swimming so possibly even a minimum of 5ft would be better. Don’t make the mistake of buying one of these for a small tank as they are often sold when they are very small, only 2cm’s in size and they look too cute at that size but will soon outgrow small tanks.
    My Info: Very peaceful fish and spends most of its time swimming in the water column, it likes to sleep on its side underneath rocks, so don’t panic when you see this for the first time. They seem to enjoy most types of short microalgae. Loves Nori.


    Powder Blue Tang - Acanthurus leucosternon

    Maximum Size fish grows to: about 20 cm’s
    My Info: Although this fish is another great algae eater, you should be wary of it as it comes with a few issues, it is highly prone to whitespot and is also known to be an extremely aggressive fish in an aquarium, if you want to add one I would recommend making it the very last fish you add to your aquarium and also try and find a small one. I owned two of these over the years and they absolutely hated new inhabitants being introduced to the tank, so much so that they killed off some of the newly introduced fish. Having said that, some aquarists have experienced no problems. But still, a truly stunning fish with amazing colours, it’s hard to find another fish with such beautiful markings and colours as this one.


    Yellow Eye or Kole Tang - Ctenochaetus strigosus

    Maximum Size fish grows to: about 17cm’s
    My Info: A bit of a plain looking fish from a distance, but these guys are true workhorses and spend almost the entire day grazing for algae. They seem to be especially fond of grazing on the glass and you will often see their ‘kiss marks’ on the glass where they have been.


    Yellow Tang - Zebrasoma flavescens

    Maximum Size fish grows to: 15 to 20 cm's
    My Info: A very hardy fish and enjoys macro algae and filamentous algae. I haven’t owned one of these for very long but from the short time that I have it spends a lot of time swimming around gracefully and its colouring is fantastic, loves to graze on the rocks and also enjoys Nori.


    Sailfin Tang - Zebrasoma desjardinii or veliferum

    Maximum Size fish grows to: 40cm’s
    My Info: Enjoys green hair algae and looks very graceful when it opens up its huge fins. A big swimmer as well so needs a large tank to accommodate it ideally.


    These next two fish I have never owned but thought they should be worth a mention as I spent a lot of time looking into which herbivorous fish to buy and these two were prime candidates but I didn’t buy these particular ones as I chose other species instead, mostly due to availability at the time, so please do consider these ones as well.

    Combtooth Blenny – Atrosalarias fuscus or Ecsenius namiyei
    Maximum Size fish grows to: about 10 cm’s so ideal for nano tanks of about 100 litres.
    More Info: Apparently they have about 100 very fine teeth on their lips which makes them excellent grazing fish for scraping microalgae off the rocks and glass.

    Tomini Tang – Ctenochaetus tominiensis
    Maximum Size fish grows to: 15cm’s
    More Info: Will fight with other tangs similar to it so be careful when choosing tangs for your tank. But a similar algae grazer to the yellow tang I believe.

    p.s. Don’t forget your regular clean-up crew of snails and hermit crabs.

    If anybody has any other recommendations, please feel free to share them, thank you.