Siamese Algae Eater: Care, Size, Tank Mates, and Habitat

When looking for fish to add to your tank, you can sometimes get lost in the number of freshwater varieties there are, but other times you’re looking for a fish to fill a particular role.

Siamese algae eaters fill a particular role, they’re perfect for someone looking for a fish that will help to tidy up their tank by clearing algae.

They’re active and social creatures that will do well in both large groups, and when kept alone. At feeding time they’re easy and will eat anything put in their tank.

Because they’re peaceful, these fish are ideal for beginners to add to their community aquarium. One thing to look out for is the Siamese flying fox which looks almost identical to the algae eaters and as a result, they are often confused.

Siamese Algae Eater Facts & Overview

Siamese algae eaters, or Crossocheilus oblongus, are freshwater fish from the Cyprinidae family. This family contains carp too, which are closely related.

They originated from Southeast Asia, including Thailand and Malaysia, but now they’re bred across the world for the aquarium trade. The reason they’ve become so popular is that they’re one of the best algae eaters available. They move around a lot, so they cover the whole tank quickly.

While the movement helps with the algae, it keeps your tank active and interesting too. Lots of other algae eaters don’t move much (like nerite snails).

Most pet stores sell them because of their popularity, so they’re easy to find. They’re cheap too, at around $3-$5 per fish.

These fish are great for beginners, they make the job of keeping the tank clean much easier and their behavior is unlikely to be an issue. That being said, Siamese algae eaters produce waste just like any other fish. Overstocking can make your tank messier rather than cleaner.

Typical Behavior

Most of their time is spent in the bottom levels of the tank. Here they swim around until they find a spot covered in algae, they’ll likely sit here until it’s gone.

If you keep a few together they’ll form groups and you’ll find them feeding together in the same area.

They’re rarely aggressive, but they’re quite energetic and swim around quickly. This means that they shouldn’t attack other fish but might disturb and unsettle any calmer species.

If they are aggressive then watch them closely for a couple of days, they might have to be separated if the problem persists.

Appearance

True Siamese algae eaters have a long, narrow body that reaches up to six inches. They’re usually a pale grey or gold with a black stripe that spans from the head to the tail.

You might find that the stripe begins to fade; this could be during a mating display, times of stress, or a way to camouflage themselves (which is less common in the aquarium).

There are no differences between males and females until around 3-4 years old, and at this point the only thing that gives away their sex is size. Females are around 30% larger in mass than males.

Siamese Algae Eater vs Flying Fox

The Siamese flying fox (Epalzeorhynchos kalopterus) often gets mistaken for the algae eater because they look so similar. They both have a bold, black stripe running down their body.

The easiest way to work out which species you are looking at is to check for flaps in the corner of the mouth. Flying foxes have them but algae eaters don’t. However, this is nearly impossible to check when the fish are alive and swimming around, so you can make an educated guess by looking at the color.

The black stripe on the flying fox tends to be smoother and it ends where the tail fin begins. The algae eaters are less uniform and stretch to the end of the tail fin.

Habitat and Tank Conditions

In the wild, you will find Siamese algae eaters in the densely planted rivers and streams of Southeast Asia. These are the same habitat preferences of closely related Asian Carp.

These tropical waters are slightly acidic and don’t tend to have a fast current. Under the surface, you will find lots of plants, rocks, and logs that provide shelter.

An algae eater’s time is split between hiding in these shelters and searching surfaces for foods. This is mainly algae, but also other things that sink to the bottom of the river.

They’re not the best explorers, they tend to stay around shelters they’re familiar with and rarely venture up to the surface of the water.

Their ideal home setup is a recreation of this natural habitat.

Tank Conditions

As they spend most of their time near the bottom of the tank, a sandy substrate makes it safer for them to swim around without scratching their body or damaging their sensitive barbels.

Plants should be added to make them feel at home. They act as shelter while keeping the water cleaner and oxygenated.

There’s a chance that your fish will start nibbling at some of the plants if they can’t find any other food. Keeping them well fed is the best way to protect your plants. One strategy is to use fast-growing species, like hornwort, that can quickly recover if any parts get eaten.

All fish like to have somewhere they can hide away from their tank mates, bottom-dwelling fish especially. Create caves around the tank to give them an escape. They aren’t territorial so there shouldn’t be any squabbling over who goes where.

Most fish can jump, but some can do it better than others. Siamese algae eaters are active and quick which makes it easier for them to jump from the water. Keeping a lid on the tank makes sure that you don’t come home to a fatal escape attempt.

You’ll need a heater to keep the water within a range of 75-79°F. Water hardness should be 5-20 dH.

Ideally, the pH would be between 6.5 and 7.0, but they can tolerate a slightly wider span if necessary (roughly 6.0-8.0).

They don’t have any special water flow requirements, which might be surprising since they naturally live in rivers. These would be slow-moving and the current would be even weaker at the river bed where they live.

What Size Aquarium Do Siamese Algae Eaters Need?

They will need at least a 20-gallon tank.

How Many Siamese Algae Eaters Can Be Kept Per Gallon?

You will need 20 gallons for the first fish and an extra 10 gallons per fish added after this.

Tank Mates

Siamese algae eaters are peaceful creatures which means there’s a long list of potential tank mates. This makes them good candidates for a community aquarium.

Since these fish spend their time at the bottom of the tank, you need to think about what else will be living there too. Lots of bottom-dwellers can be territorial or just bully those that get in their way. Red tail sharks are a good example; they harass others to protect their territory when they mature. This isn’t a battle your peaceful algae eaters would win.

There are plenty of peaceful bottom-dwellers for you to choose from. Corydoras are some of the most popular; this genus contains lots of different species.

Fish that live in other areas of the tank won’t have any territory disputes so there’s an even wider selection. Don’t add any notoriously aggressive fish because they might attack or eat your algae eaters.

This usually means avoiding cichlids, many of which should only be kept in a species-only tank anyway. There are some peaceful exceptions though, like angelfish.

Tetras, danios, and guppies work well because they’re small and not aggressive. You can also use bigger fish like gouramis and barbs because their size doesn’t come with added aggression.

It’s good to remember that your tank mates don’t have to be fish. Other animals can be added, most of which tend to eat algae too. The most common are shrimp (amano, cherry, and ghost) and snails (like nerite snails).

Mixing in shrimp and snails with your fish shows off some different behaviors, adding extra interest to your tank. They still contribute to the biological load of the tank though so don’t overstock your aquarium.

Keeping Siamese Algae Eaters Together

You can keep more than one Siamese algae eater in the tank. They show off their best behaviors in schools of at least 4-6.

This doesn’t mean that you need to keep them in a school though, they do well when kept singly or in pairs too.

Diet

The main part of their diet is in their name. In the wild they would eat algae, plant matter, and vegetation but they’re not just herbivores. They’re scavengers so they will eat whatever they find, including dead fish and insects.

It’s easy to provide for them in the aquarium, they are not fussy and will eat most things you add to the tank. This includes flake and pellet foods from stores, algae wafers and live foods. Good examples of live foods are brine shrimp and bloodworms, frozen varieties will work well too.

Sinking foods like pellets are good for bottom-dwelling fish as they’re more likely to fall past fish higher up in the tank.

Overfeeding can be a problem because they already have some algae and plants in the tank before feeding time. Sometimes Siamese algae eaters will stop eating algae in favor of the other foods you give them if you keep adding too much.

They can eat a lot, they would eat all day if you let them. Limit feeding to an amount that they can easily finish in a couple of minutes each day.

Care

There aren’t any specific diseases that these species are prone to, but that doesn’t mean they won’t get ill at some point.

Most diseases give off signs, some are more obvious than others. For example, the common Ichthyophthirius multifiliis parasite (generally known as “ich”) causes small white dots around the body.

Lots of diseases have treatments and medicines that you can buy which work well with quarantine tanks, but there are ways to help prevent your siamese algae eater getting diseases in the first place.

• High-quality foods are less likely to cause organ problems. Cheaper foods can cause constipation which often leads to further effects.
• Dirty water is like humans breathing polluted air, so water changes should be done every two weeks to reduce the buildup of pollutants.
• Be careful what you add to your tank. Decorations can carry toxins, and water from other aquariums might bring diseases.

Breeding

It’s unlikely that you’ll be able to breed these fish yourself, even though they mate in the same way as lots of other fish. They’re only known to breed in farms with the aid of hormones.

Simply sexing them is hard enough and needs a keen eye. Females are about 30% larger once fully matured.

Spawning could probably be triggered by changes in water conditions (temperature, pH, etc.), but currently little is known about how to breed them in home aquariums.

Are Siamese Algae Eaters Suitable for Your Aquarium?

Whether you’re new to fishkeeping or you’ve been doing it for years, you shouldn’t have a problem keeping Siamese algae eaters happy and healthy.

They’re peaceful and hardy so less likely to fall victim to beginner mistakes.

If your tank contains plants, peaceful fish, and has enough free space, they will thrive.

In return, your aquarium will look cleaner and more lively.

Siamese Algae Eater FAQs

• How long do Siamese algae eaters live?
• What do Siamese algae eaters eat?
• Can Siamese algae eaters live with guppies?
• What is the difference between a flying fox and a Siamese algae eater?
• Are Siamese algae eaters fin nippers?
• How many Siamese algae eaters can I keep in a 20-gallon tank?
• Can betta fish live with Siamese algae eaters?
• How many Siamese algae eaters should I have?
• Do Siamese algae eaters eat algae?
• How big do Siamese algae eaters get?
• Can I keep one Siamese algae eater?
• Are Siamese algae eaters aggressive?