Are Siamese Algae Eaters Aggressive?

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If you are a beginner aquarist looking to keep a Siamese Algae Eater, then we are here to tell you that you have made the right choice. Among all the freshwater fish, they are one of the most peaceful species that are also easy to care for.

Siamese Algae Eaters are Schooling Fish

Siamese Algae Eaters are Schooling Fish

Since they are schooling fish, it is best to keep 5 or 6 of them in the aquarium. Fish breeds with peaceful temperament are usually much less demanding and the Siamese Algae Eater is no exception. They will not pose a threat to any other fish you put them together with.

You just need to be sure that the fish you have chosen is indeed a Siamese Algae Eater. There is another species called the Siamese Flying Fox and it is surprisingly difficult to distinguish between the two. They have a slightly different temperament, as Flying Foxes tend to be aggressive towards their own breed.

But when it comes to other species, they are just as peaceful as Algae Eaters.

Algae Eaters are Too Busy to Deal with Conflicts

This is the type of fish that will be so busy finding and eating algae in your tank that it won’t bother anyone with its presence. The Siamese Algae Eater spends most of its time in the bottom layer of the fish tank, diving into the substrate and looking for algae.

If you see them swimming around, they are usually looking for algae-covered spots where they can get to work.

The only problem might be that Algae Eaters get so excited about eating algae that they don’t care about bumping into other fish as they swim through. If you put more than one of them in the tank, they will group up and eat algae together.

Therefore, territorial species can get really mad at them. Not to mention that many fish get rather aggressive and territorial during their breeding and spawning season.

Algae are not the only source of nutrition for the Siamese Algae Eater. Although they love it, they are still omnivorous species.

You need to supply them with live food and any other meat-based food from time to time. This is mandatory for their proper nutrition. Sure, they would eat algae all the time but all in all, that is not good for their health and there are also vitamins they need to get from elsewhere.

Territorial Temperament between Siamese Algae Eater Males

Siamese Algae Eater Males are Territorial

Siamese Algae Eater Males are Territorial

There is pretty much only one situation when the Siamese Algae Eater turns aggressive. Since they are schooling fish that love to swim around and eat together, there has to be at least 5 or 6 of them in the same tank. In smaller schools, the males become stressful and it will bring out their territorial temperament.

Therefore, you should decide whether you want to care for a single Siamese Algae Eater or a whole school of them. They have no problem with other species and they can eat plenty of algae alone as well. Or you can completely avoid this issue by buying only female algae eaters who will get along well if you put them together.

If you want to buy many of them or even populate the whole tank with only Siamese Algae Eaters, then the rule of thumb is to pick mostly females.

Do Siamese Algae Eaters Get Along Well with Bottom Dwellers?

Even if you are looking for only bottom-feeding fish, there are many species to choose from with different temperaments. The Siamese Algae Eater is a rather peaceful part of this family. However, there are also plenty of semi-aggressive and territorial fish to choose from.

If you want to add more bottom dwellers to your tank, then you should choose carefully. You need to put your Siamese Algae Eaters together with tank mates that won’t harass them. All in all, you shouldn’t keep any fish in your tank that would interact unhealthily with the fish around them.

The Red Tail Shark is one species you should definitely avoid putting them together with. What we recommend instead are Plecos that are smaller than your SAE and the peaceful Angelfish.

These won’t bother each other at all. You can add some diversity to your tank as well by populating it with shrimp and snails.

Recommended Tank Conditions for the Siamese Algae Eater

A single Siamese Algae Eater feels comfortable in a 20-gallon tank. For each additional SAE that you want to add, you need to expand your fish tank by 10 gallons. In order for this species to be the most active and lively version of themselves, you need to recreate their natural habitat.

While designing your fish tank, you need to focus on the bottom layer. Insert a couple of bigger rocks or wood pieces where your Algae Eater can hide. After they have eaten enough algae, they go back to their shelter and won’t come out for a while. You can rarely see them swimming up toward the surface of the water.

If you add enough plants to your aquarium, the Siamese Algae Eater will truly feel at home. Since the bottom of the tank is where they mainly swim around, make sure that your substrate is soft and there is nothing that can scratch their body.


All in all, we can only recommend Siamese Algae Eaters for both beginner and more experienced fish keepers. They love algae, they are really not demanding and, most importantly, they go along quite well with other species.

If you manage to keep your Algae Eaters healthy and lively, they will keep your aquarium clean in return. Make sure that you choose some peaceful fish for tank mates and consider adding another 5-6 of them so that they can thrive together.

Without them, you might need to use chemical substances to clean your tank or other tricks that might be time consuming.

Siamese Algae Eaters not only solve your problem but they have an interesting personality as well. This peaceful species is always a great addition to a community tank.  

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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