7 Best Freshwater Aquarium Algae Eaters

Algae eaters can be a welcomed addition to any freshwater tank when it comes to reducing maintenance time. For larger tanks, most people opt for algae-eating fish. For smaller community tanks, many shrimp & snail species are viable choices. Depending on the type of algae growing in your tank, you may want a different type of algae eater that really loves that type of algae.

It’s important to keep in mind that algae are not the only thing most algae eaters will eat. For instance, when it comes to plecos, they require real wood in your tank as a supplement to their diet. A lot of algae eaters tend to end up eating your fish food and in some cases develop taste buds only for fish food and no longer for algae!

You should also keep in mind the overall compatibility of the other fish in your aquarium. Some breeds of plecos and Chinese algae eaters, for instance, can get more aggressive as they age. Last but not least, make sure the water parameters of your algae eater matches that of your tank. On to the list!

1. Plecostomus (pleco)

  • Temperature: 23-28c ; 73-82F
  • PH:5.6-7
  • Size: 5 inches++

One of the most common algae eaters on the market. When buying one, make sure to take note of the breed as many plecos grow to a very large size (common – 18inches, bristle nose – 5inches). If you have an immediate algae problem, go with a young/baby pleco and he will eat up your mess in no time.

For both size and behavior, I would avoid the common pleco and go with something like a bristlenose pleco or even fancier. You will need real wood in the tank as well as potentially algae wafers as their top foods. Sinking things like cucumber chunks are also one of pleco’s favorite treats! Keep in mind that plecos are poop factories and will greatly affect your water conditions. If you have sensitive fish or are a bit lazy on the maintenance end you may want to think twice.

2. Otocinclus Catfish (Ottos)

  • Temperature: 20-26c ; 68-79F
  • PH:6-8
  • Size: 1.5inches

The Otocinclus Catfish is a great small algae-eating fish that does well in most tanks. Their adult size reaches only about 4cm which makes them versatile in many tank sizes than compared to plecos. Ottos are schooling fish so be prepared to buy them in a group of 4 – 6. Being bottom feeders, they will over time get used to eating the scraps left over from your fish food just so you are aware. Ottos eat specifically soft algae and also are great at eating algae off plants without harming the plants.

Being a smaller fish, you may have issues if housing them with more aggressive type cichlids, who if large enough may try to eat them.

3. Siamese Algae Eater

  • Temperature: 24-26c ; 75-79F
  • PH:5.5-8
  • Size: 6inches

The Siamese Algae Eater hails all the way from the regions of Thailand/Malaysia. It’s not uncommon for these guys to get mixed up with the Otto and Chinese Algae Eaters. The best way to identify them is by their black stripe all the down the middle to make sure you’re buying the right fish.

It is a fairly hardy fish that prefers faster-moving waters, so keep that in mind when incorporating with other tank mates. They tend to favor brush, thread, and red algae over other types so if you have one of those here’s your solution. SAE’s are quite suitable for community tanks and can be kept in groups, however, like most groups of fish a pecking order may be established leading to aggression.

They do best in water temperatures of around 25 C and require optimal water conditions to thrive well. Both ottos and SAE’s prefer to have places to hide, forage, and clean making them ideal for planted tanks. Please keep in mind that their final size can reach around 6 inches so plan accordingly.

4. Amano shrimp

  • Temperature: 22-26c ; 72-79F
  • PH:7-7.5
  • Size: 1-2inches

One of the most popular shrimp species, the Amano shrimp are the ultimate aquarium nannies. Not only do they eat algae, but they clean up leftover food scraps and decaying plant matter. Although starting out quite small, they can reach an end size of around 2 inches in length which is still good for many smaller aquariums.

They are great to have in groups and it’s not uncommon for people to have shrimp-only tanks. Some drawbacks are that these shrimp can become food for larger fish, so they definitely require very passive fish species if put into a community tank. Other people have succeeded in keeping them with fish by having heavily planted tanks giving the shrimp plenty of places to hide and reproduce on their own.

If you go the planted route keep in mind that if using any type of fertilizer, any copper residual found in it will be harmful to Amanos. The same can be said for medicating tanks, where almost all fish meds containing heavy metals that will kill your shrimp. If you need to treat a community tank with either fertilizers or meds, remove the shrimp first.

5. Ramshorn Snails

  • Temperature: 24-26c ; 75-80F
  • PH:7-7.5
  • Size: Up to 1 inch

Well unless you’re really into snails (snail tank), I would steer away from this algae eater. Lots of people have bought Ramshorn snails to fix their algae problem, only to be left with a massive Ramshorn snail population taking over their tank. If this is already a problem for you, an easy remedy is to buy assassin snails (what a cool name!). They will make quick work of your snail population problem. If you ever buy plants, there’s a small chance there are Ramshorn snails sneaking on board.

If you’re still keen on getting these snails, they reach an average size of about 2cm. They have been known to munch on any vegetation you have going on in the tank but focus primarily on algae on all surfaces. If you are running a breeding tank (which should preferably only housing that one species), these snails may potentially eat the eggs.

Quite a few fish will eat snails, and if you want to go into some of the more unique species of fish I would leave these guys out of your choices. That being said, they make a lot of fun for smaller planted tanks if that’s the route you are trying to go (10 gallon and under).

6. Hillstream Loach

  • Temperature: 20-24c ; 68-75F
  • PH:7-8
  • Size: Up to 3inches

The Hillstream Loach is an awesome little fish if you’re going with a cooler water tank. Just as their names suggest, they come from fast-moving water such as streams and rivers. The two key elements to keeping a happy loach are to have a strong water current and colder tank temperatures as they require very high oxygen levels.

Aside from algae, just like most algae eaters, they enjoy the occasional algae wafers and my personal favorite blood worms. Although there are several varieties of these little guys, most likely your fish store will only be carrying the spotted type. If you want to splurge you can find other varieties online and ship them to you but I probably wouldn’t for just a loach.

Oh lastly, they are very peaceful fish and should be kept with similar temperament aquarium buddies!

7. Whiptail Catfish, AKA Twig Catfish

  • Temperature: 22-26c ; 73-79F
  • PH:5-7
  • Size: Up to 6inches

The Whiptail Catfish is a fish I am slightly biased towards as it hails from the lakes and rivers of the Amazon. Unfortunately for me, I haven’t seen these beauties at any of my local fish stores, but enough about me. They pretty much look like as their nickname suggests, a very long and skinny twig.

I find it kind of interesting that they have an elongated nose but have a suckermouth. And we all know what that sucker mouth is for, eating up delicious algae and leftover food. They are however once again a more peaceful fish and it’s highly recommended to have some kind of rockwork or driftwood for hiding spots as they can be easily stressed.

If you’ve ever wanted one of those twig insects as a kid well, here’s a slightly similar aquatic version. Oh the last thing, they can grow up to 6 inches so beware! No small tanks for these guys.

I tried to mix up both useful and unique algae eaters into the list. Do you have any suggestions? Post them in the comments below!

When should I add algae eaters to the tank?

It’s generally best to add algae eaters to your aquarium after it has been fully cycled and established for at least a month. This allows the tank to develop a stable biological balance, and more importantly, for algae to begin growing. Algae eaters need a food source, and introducing them too early may leave them without enough to eat.

Before adding algae eaters, make sure to research their specific needs and compatibility with your current tank inhabitants. Additionally, monitor your water parameters to ensure they are within the acceptable range for the algae eaters you plan to introduce. When you do add them to the tank, make sure to acclimate them properly to minimize stress and help them adjust to their new environment.

Do algae eaters not like light?

Algae eaters have varying preferences when it comes to light. Some algae eaters, like the Otocinclus catfish and certain species of plecos, prefer dimmer environments and may hide when the tank lights are on. They are more active during dawn and dusk, or when the tank lights are off.

However, many algae eaters will still be active and eat algae during the day, despite their preference for lower light conditions. It is important to provide hiding spots, like caves, driftwood, or plants, to give them a place to rest and feel secure during the day.

As a general rule, maintain a consistent day-night cycle in your aquarium to support the health and well-being of all your fish, including algae eaters. This can be done using a timer for your aquarium lights, which can help regulate the light cycle and provide a more natural environment for your fish.

What do algae eaters eat if there are no algae?

If there are not enough algae in your aquarium to support your algae eaters, you’ll need to supplement their diet with other foods to keep them healthy. It is essential to understand the specific dietary needs of the species you have in your tank, as their requirements can vary. However, here are some general suggestions for supplementing the diet of common algae eaters:

  1. Algae wafers or tablets: These are commercially available and specially formulated to provide algae eaters with a balanced diet. They usually contain various types of algae, as well as other essential nutrients.
  2. Vegetables: Blanched vegetables, such as spinach, zucchini, cucumber, lettuce, and peas, can be a great source of additional nutrition for many algae eaters. Make sure to remove any uneaten vegetables after a few hours to prevent water quality issues.
  3. Spirulina: Spirulina is a type of blue-green algae that is rich in nutrients and can be good supplemental food. It is available in various forms, including flakes, pellets, and powder.
  4. Live or frozen foods: Some algae eaters, particularly certain pleco species, may require additional protein in their diet. Supplementing with live or frozen foods, such as bloodworms, daphnia, or brine shrimp, can provide the necessary protein.

It’s important to observe your algae eaters and monitor their overall health. If they appear to be undernourished or not eating enough, consider adjusting their diet and consult expert advice if needed.


5 Responses

  1. Personally I prefer gyrinochrilus, which comes in golden, stribed and spotted varieties. They aren’t suited for small fish like guppy, platy, molly and tetra, which they might eat or wound. They can be aggressive, but they keep my tank clean. To make them breed, they need the aquarist nightmare: unclear water and little light. It doesn’t look nice and is seldom suited for other fish.

  2. this is just like the major kinds of species of algae eater… i have 2 golden chinese algae eater they really look alike the siamese except for the color … but well i was going to buy shrimps but they were too small when i saw them i was like … my comet would eat that in a split second and he didnt even knew what it was… or is it ok to put tiny shrimps whit big fishes?

    1. It’s important to note here that the Siamese Algae Eater does not look like the Chinese Algae Eater. Take a good look at the head shape on each animal. The CAE (aka Sucking Loach) has a pronounced sloping forehead and flattened underside to the skull, and its jaws form a large Pleco-like sucking disc – this is easily visible when it sucks against the front glass of the aquarium. The SAE (aka Siamese Flying Fox) has smoother, more pointed & ‘shark-like’ head shape and its mouth visibly consists of two separate thick browsing lips. This highlights the very different feeding methods of the two species; the CAE latches onto a surface and rasps at soft growths or biofilms, whilst the SAE hovers over a surface and nibbles at filamentous algae in a manner which the CAE will not and cannot, for one major reason. What is this reason? The CAE has an ineffective swim bladder and sinks when not actively (and powerfully) swimming, unlike the graceful SAE which can float gracefully even when not actively swimming forwards. There are numerous other differences, all borne of the unique & very dissimilar environmental circumstances under which these two species evolved. There need never be any confusion between the elegant & shark-like SAE and the hunchbacked, ungainly CAE!

  3. I have a pleco, and let me warn you… i got him when he was about the size of my thumb LESS THAN A YEAR AGO! he is now the size of my HAND! Huge. Oh and i do like Dragon Fish *aka Violet Gobi’s* they are eel-like in appearance and actually SHIFT the sand or gravel. He too is getting big, and will get to be larger than… the circle your fingers and thumbs can make put together.

  4. In my opinion, one of the greatest new algae-eater additions to the hobby in recent years has been the amazing Panda Garra (Garra flavatra). This striking fish has a stockier body than the Siamese Algae Eater, with a much broader and bluffer head shape, but shares the thick, underslung browsing lips and penchant for stubborn fluffy algae. It will also eat soft green filamentous algae and even graze away the green haze which clouds the front glass. The only algae that it will not attempt to tackle is the blue-green velvety slime of cyanobacteria growths. It’s a friendly, active and gregarious fish that will live alongside other loaches and catfish without making trouble, and can be kept singly or preferably in groups. The body colour is chocolate brown and buttery yellow bands and the fins are a reddish color, making it very attractive. It will adapt to many different freshwater parameters (soft or hard) and grows to a little more than three or four inches. If it has any drawbacks, it is a requirement for high dissolved oxygen levels, so an aerator is recommended. Otherwise, a fish with absolutely no drawbacks at all

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