Siamese Algae Eater Care, Information, & Pictures

While they are rarely very colorful, algae eating fish are essential for most fish keepers. Since any aquarium is far more heavily stocked than wild environments the water is full of nutrients that fuel algae growth.

Siamese Algae Eaters are excellent medium sized algae eaters that can thrive in most community tanks. Since they are a little subdued in color and often sold small, they may be skipped over in favor of other algae eaters. Instead, let’s take some time getting to know this special little Asian carp!

Being cyprinids they are closely related to Goldfish, Barbs, and Danios. Most cyprinids are hearty omnivores that love a mixture of animal and plant material. Siamese Algae Eaters are as well but lean heavily towards the vegetarian end of the spectrum!

They are also quite a bit more sociable than most bottom dwelling algae eaters. Some of the usual choices tend to be both large and territorial. However Siamese Algae Eaters keep to themselves and are very peaceful towards their tank mates.

  • Common Name: Siamese Algae Eater
  • Scientific Name: Crossocheilus oblongus/siamensis
  • Origin: Southeast Asia
  • Length: 4-6 inches
  • Aquarium Size: 20+ Gallons
  • Temperament: Peaceful
  • Ease of Care: Very Easy
Siamese algae eater

Siamese Algae Eater Care

This section covers everything you need to know about Siamese Algae Eater care:

Aquarium Size

Siamese Algae Eaters are not as small as other commonly available algae eaters. They are right in the middle of the size arena, reaching adulthood between 4 to 6 inches in length. They shouldn’t be kept in aquariums smaller than 20 gallons, with 30+ being better for them.

These are the best algae eaters for community tanks with medium sized fish like Gouramis, Barbs, Dwarf Cichlids, and Catfish. They also do well in larger community tanks but make sure their tank mates aren’t lareg enough to eat them.

Siamese Algae Eaters can be kept single or in small groups, in which case, you should give each fish roughly 10 gallons of space. While not extremely aggressive they can be territorial towards one another.

Typically, the males are the worst when it comes to this behavior. Unfortunately, it is impossible to visually tell the difference between males and females until they are fully grown.

So if keeping a group err on the side of caution. Also it becomes much harder to grow enough algae and biofilm to feed several Siamese Algae Eaters in a smaller aquarium.

Water Quality

Siamese Algae Eaters come from Southeast Asia where the waters tend to be soft and acidic (pH 6.0-6.5). However, they thrive in both neutral (pH 7.0) and even alkaline conditions (7.0+).

Temperature-wise, they do best around 75-80℉ but will tolerate a few degrees warmer or colder. The majority are captive bred and used to the fluctuating conditions of warehouse fish shippers.

As a result they are extremely hardy, tolerant of elevated ammonia and nitrite levels, and will even breed in parameters outside of their favored conditions.

But don’t use this tolerance as a reason to get lax on water changes. The aquarium nitrogen cycle can only process so much waste before ammonia, nitrites, nitrates, and other elements become toxic even for the hardiest of fish.

Plants and Substrate

Siamese Algae Eaters are generally plant-safe, so long as they have ample algae and biofilms to eat. They should be kept in aquariums with live plants since the high light and nutrient levels also grow their favorite foods.

They may have a taste of soft leaves or decaying plants on occasion. However they typically don’t do visible harm. Eating live plants is a sign that they aren’t getting enough food and you should start offering some of the options discussed below.

Live plants also oxygenate the water, create shade, soak up nitrates, and foster a sense of security for these occasionally shy fish.

The substrate should be one that helps grow live plants. Sand or gravel is pretty irrelevant to Siamese Algae Eaters. Choose one that you get the best growth for the plants you intend to grow and is the most aesthetically pleasing!

I also recommend adding driftwood, rocks, and other flat surfaces that hold space for algae to grow. Driftwood in a well lit patch grows both algae and biofilm. They also create shelter, are beautiful to look at, and release plant tannins that buffer the water towards acidity!

Siamese Algae Eater

Tank Mates for Siamese Algae Eaters

Siamese Algae Eaters are model community tank residents. Chinese Algae Eaters and Plecostomus tend to be not only aggressive but sometimes latch onto slow moving tank mates to have a taste of their slime coats.

Siamese Algae Eaters stick entirely to algae, vegetables, and biofilms. They are even gentle on soft leaved plants like Cabomba and Anacharis (so long as they are well fed on algae).

Unlike most algae eaters they can also be kept together. Groups are better than pairs because while they will occasionally shoal they are mostly territorial.

Siamese Algae Eaters aren’t typically murderously aggressive and don’t have large teeth that do a lot of harm. But if one fish is continually bullied it can become fatally stressed. It’s best to only keep multiple Siamese Algae Eaters in aquariums 30 gallons or larger.

Good Tank Mates for Siamese Algae Eaters

  • Goldfish and Barbs
  • Guppies, Mollies, Gouramis, and other Community Fish
  • Snails, Larger Shrimp, and other invertebrates
  • Other Siamese Algae Eaters (with caution)

Avoid keeping Siamese Algae Eaters with aggressive bottom dwellers. Red Tail Sharks, many large Catfish, and most Cichlids are territorial and quick to start a fight with anything that invades their territory. If you must keep them together, make sure there are plenty of hiding places and breaks in line of sight for the tamer species.

Poor Tank Mates for Siamese Algae Eaters

  • Aggressive Cichlids
  • Large Catfish
  • Red Tail Black Sharks
  • Botia sp.
  • Chinese Algae Eaters

Feeding Siamese Algae Eaters

As their name suggests, Siamese Algae Eaters spend most of their time grazing on the algae that grows in most tanks. They dart about, nibbling away at the glass, leaves, rocks, and other flat surfaces that form miniature gardens underwater.

Siamese Algae Eaters also consume biofilms that contain bacteria, diatoms (brown algae) in small amounts, and other microorganisms.

There are tons of algae eating fish available in the trade: Plecostomus, Chinese Algae Eaters, Hillstream Loaches, Nerite Snails, Amano Shrimp…Why would you choose a Siamese Algae Eater over any of these?

A major reason is their willingness to eat red algae varieties. Nearly all freshwater algae eaters ignore black beard and staghorn algae. These varieties are technically a dark green in color but the red often shows through when weakened or killed via chemical treatments. Marine macroalgae also tend to be redder.

Red algae are tough, inedible to many fish, and very hard to eliminate. So if you have an infestation, a Siamese Algae Eater may be the best choice. They also eat standard green, hair, and other forms of algae as well.

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If you don’t have loads of algae for them to eat, you’ll need to supplement their diet with more greens. Blanched vegetables like spinach and zucchini are quickly eaten. But if you don’t feel like cooking, prepared foods like sinking algae wafers are excellent!

While they are mostly vegetarian and bottom feeding Siamese Algae Eaters will also eat animal protein that’s small enough for their mouths. Bloodworms, daphnia, brine shrimp, and other live or frozen foods are fine in small amounts!

Sexing and Breeding Siamese Algae Eaters

Unfortunately, Siamese Algae Eaters are one of the many aquarium fish that are nearly impossible to visually sex. When fully mature females can be as much as 30% larger however this takes 3 to 4 years on average.

Until then, both males and females look entirely identical in terms of patterns and size. In Southeast Asia they are raised by the hundreds in outdoor ponds that get rich tropical sun that fuels constant algae growth. So there’s no need to choose males or females.

Breeding is almost unheard of in home aquaria. The best way to do so is to raise a group of 4 to 6 individuals in a heavily planted aquarium. The plants, algae, full spectrum light, and biofilms will create an ideal habitat for your Siamese Algae Eaters to eventually pair off and breed!

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