Chinese Algae Eater Care Guide: Size, Tank Mates and More…

One of the most frustrating things to manage in an aquarium is algae growth. That’s why many aquarists prefer to add a Chinese algae eater to their tank, hoping it will help keep algae growth under control.

But there are a few things to consider before adding one of these little fish to your tank, including the fact that their name is a little deceiving. Let’s take a look at everything you need to know about caring for a Chinese algae eater.

Chinese Algae Eater Habitat and Appearance

Before adding any fish to your aquarium, you must consider its natural habitat. If you want your fish to live long, healthy lives, you have to try to recreate this environment as best you can for them. 

The Chinese algae eater is a freshwater catfish that’s also known as a sucking loach or honey sucker. They’re native to Southeast Asia and are found in the Mekong River basin and the Xe Bang Fai River, near Cambodia, Laos, Thailand, Vietnam, and parts of China.

They spend most of their time using their mouths to stick to rocks and other flat surfaces on the riverbed, even as the current goes flowing by above them. Chinese algae eaters primarily hang out at the bottom of streams and riverbeds, eating up algae and other detritus, and their gills are developed in such a way that they don’t have to release their grip to breathe.

Chinese Algae Eater

Chinese algae eaters have a long, thin body with small fins. They look a lot like other pond fish that spend their time at the bottom of a river or aquarium, though they’re a little bigger than most. In the wild, they can get up to 11 inches long, but they usually only reach about five inches in an aquarium environment.

Chinese algae eaters are pale brown with a dark stripe down the side that sometimes break into spots. Most kept in an aquarium maintain these colors, though albino varieties that are gold in color are also available.

Learn as much as you can about this fish before adding it to your aquarium. This is true of any fish, but especially this one. They live anywhere from five to 15 years, so there’s a chance you’re going to be taking care of it for quite a while!

All in all, the Chinese algae eater is a fascinating fish, but don’t let their name fool you. There is a lot more to these aquarium fish than meets the eye. Is it right for your tank? Let’s take a closer look.

Tank Size and Environment

Juvenile Chinese algae eaters are about two inches long. You might see them in a pet store and think they’d be a good fit for your 10 or 20-gallon tank, but they grow into a larger fish and need a lot more space than you think.

As we mentioned, adult Chinese algae eaters in an aquarium environment usually grow to about five inches, but they need a lot of space when fully grown. Remember, they’re found in large rivers and streams in the wild, so the species is used to having a lot of room. When they’re young, a 30-gallon tank will do, but some people are surprised to learn that a single Chinese algae eater needs at least a 50-gallon tank when full-grown, even at five inches. If you’re planning to keep two or more, the tank should be at least 100 gallons.

As for tank set up and environment, it’s always a good idea to attempt to recreate the fish’s natural environment. For a Chinese algae eater, that means a river rock bottom, driftwood, and rocky or sandy substrate. Most plants are safe, and bright lighting is a must to encourage algae growth, especially when the fish are young. These fish don’t care for cute decorations, castles, and other embellishments. Staying as natural as possible with a freshwater aquarium is the best approach.

Chinese Algae Eater in Tank

Because they are used to the constant movement of river water, Chinese algae eaters need a bit of a current, which can usually be accomplished with a hang-on-the-back filter as long as it has a powerful return. In larger tanks, it’s a good idea to get an underwater powerhead or pump to create a stronger current.

Another thing to keep in mind is that Chinese algae eaters are very sensitive to water conditions. Frequent water changes are essential to keep nitrates under control. They need highly oxygenated water, too, with a temperature between 75 and 80 degrees F, but they can tolerate a wide pH range from 5.8 to 8.0.

Cycling the Tank

Cycling a new tank is always important, but it’s especially so with Chinese algae eaters. They need pristine water, and that is not possible unless the tank is properly cycled. Most people with aquariums already know the importance of cycling, but there are a lot of people who don’t understand how long the process takes.

Tank cycling is all about the nitrogen cycle. When waste builds up in the tank and begins to break down, ammonia is released into the water. Ammonia is toxic to fish, but beneficial bacteria grow in the substrate and filtration media, digesting ammonia and turning it into nitrites. Though not as deadly as ammonia, nitrites are also harmful to your fish. The bacteria break it down even more into nitrates.

Nitrates are not harmful to most fish. In most tanks, nitrates are a good sign because they show that the bacteria are effectively breaking down the ammonia and nitrites. That said, Chinese algae eaters do not tolerate nitrates well. This is why it is so important to make sure your tank is properly cycled before adding a Chinese algae eater.

There are two approaches to the cycling process. The first is using a small number of hardy fish to naturally introduce waste to the tank. White cloud minnows, zebra danios, and tiger barbs are all good options that are compatible with Chinese algae eaters.

For a 50-gallon tank, add five or six fish to the water. Be very careful not to overfeed them so as not to add too much waste. This causes a big spike in ammonia and can be very stressful for the fish, making them more susceptible to disease or even death.

Every two days or so, perform a 10 to 15 percent water change. After about a week, test the water. You can use a home kit or test strips or take a water sample to your local pet store. Most will test it for you, and some will even do it for free.

At this point, the water should have high ammonia and a small number of nitrites. Nitrites show that there are bacteria present and that they’re breaking down the ammonia. The tank needs time for more bacteria to grow and begin breaking it down even further.

Chinese Algae Eater Habitat

A lot of people think that cycling a new tank takes a few weeks, but it can take up to two months. Don’t get discouraged. If you’ve set up a new tank and added fish only to have them die a few days later, it’s likely the tank wasn’t cycled long enough.

Eight weeks may seem like a long time, but it’s extremely important to get this right with Chinese algae eaters. Recheck the water after a few weeks. Eventually, the nitrites should drop to trace levels or zero, and the test will detect nitrates. This is also good – it means the bacteria are converting the nitrites to nitrates. At this point, cycling is complete, and you’re ready to add some fish. But you have to do it the right way.

Continue to feed your fish normally and add new fish a few at a time. Continue to check the water every few days to make sure the ammonia and nitrite aren’t spiking due to the increased bioload. The Chinese algae eater should be added last, and you have to make sure your nitrate levels are as low as possible before adding it. As we said, most fish can tolerate some nitrates, but Chinese algae eaters cannot. If you need to lower your nitrate level, feed your fish sparingly to avoid any unnecessary waste.

When doing water changes, use purified water to avoid unknowingly adding any nitrates, and check the water often.

Another way to cycle a new tank is called a fishless cycle. Rather than using live fish to introduce waste to a new tank, some people prefer a chemical bacterial booster to set off bacterial growth and the nitrogen cycle. There are pros and cons to this approach. The big plus of using chemicals is that you’re not putting any fish lives at risk. Cycling a tank naturally involves spikes in ammonia and nitrites, and some people think it’s cruel to put a fish through this. Hardy fish should be able to handle it, but you never know.

The downside is that chemical bacteria boosters don’t seem to produce the same stability as using fish. As we said, cycling with live fish takes about eight weeks or so, but a chemical supplement can take as long as six months to completely stabilize.


As mentioned, water quality is very important for these fish. They cannot tolerate nitrates, so adequate filtration is key. Use a vacuum siphon on the substrate with every water change to remove excess food and other waste.

Do a 25 to 50 percent water change every month, unless the tank is densely stocked. In that case, change 20 to 25 percent every week or two. Use a magnetic scraper to get excess algae from the glass when needed.

Tank Mates

While juveniles do okay in a community tank, Chinese algae eaters get territorial and aggressive as adults, so finding appropriate tank mates for them isn’t easy. Don’t be surprised if you have a Chinese algae eater in your tank that was docile but after bringing it home, its behavior changes and becomes more aggressive over the years. Avoid adding other bottom-dwellers as the Chinese algae eater sees the bottom of the tank as its space and will constantly harass anything that gets near it.

Wide, flat-bodied fish are also a no-no, particularly slow-moving ones. Chinese algae eaters are known to latch onto the side of these fish, sucking off their slime coat, which is a huge infection risk.

These fish are natural loners, so they don’t need other Chinese algae eaters around. That said, they can be kept in groups, preferably of three or more. If you keep them in pairs, one will become the dominant fish and bully the other one. With three, they’ll establish a natural pecking order and keep each other in line. This will also prevent them from attacking other tankmates. The ideal number to keep together is five, but that’s not always plausible. Remember, you need a 100-gallon tank or larger to house multiple Chinese algae eaters. If you have three, 150 gallons is ideal.

These fish are challenging to breed, so don’t worry about that too much when keeping a group of them. It’s also tough to identify the sex of a Chinese algae eater, especially when they’re young, so you don’t always have a choice in what sex you’re adding to the tank. If this is something that concerns you, keep the water temperature at the cooler end of the acceptable range, around 75 or 76 degrees. Some people believe that these fish are more likely to mate in water temperatures of 80 degrees or higher.

How to Keep a Chinese Algae Eater

It’s always important to prevent overcrowding when stocking your tank, especially when you’re working around a fish like this that needs a lot of space to call its own. So, what are good tankmates for a Chinese algae eater? Top-dwelling fish are your best bet because they are most likely to stay out of the Chinese algae eater’s way.

Peaceful, fast-moving fish that stay at the top of the tank is ideal, including mollies, platies, zebra danios, white cloud minnows, tiger barbs, dwarf gourami, and platies. Avoid shrimp because they are likely to be attacked or eaten, especially when the Chinese algae eater reaches adulthood.

When setting up a community tank that includes a Chinese algae eater, planning is important. For best results, set up the tank, cycle it, and add all the other fish first. After a few days, add the Chinese algae eater. We already talked about how it’s important to make sure the nitrates are as low as possible, but adding this fish last has another benefit. If the Chinese algae eater is introduced to an established tank, it will be less likely to see it as its territory and may be less aggressive.

Feeding a Chinese Algae Eater

Chinese algae eaters have a misleading name. While they do eat a lot of algae when they’re young, they’re omnivores that prefer meatier foods as they get older. A young Chinese algae eater might be happy living off of only the algae growing in your tank, but, as it matures, a more well-rounded diet is needed. If you don’t provide it, the fish might begin attacking other things in your tank.

When the fish is young, leave some algae in your tank while cleaning so it has something to hunt around for, and offer a high-quality flake food or algae wafers, too. You don’t have to do this when the fish matures. They won’t want algae in the tank anymore once they know that other food is available.

If you prefer a natural option, these fish love crushed lettuce, spinach, shelled peas, and small pieces of fruit. Supplement occasionally with brine shrimp and bloodworms to make sure they’re getting the protein that they would find in their natural environment.

Remember that these fish are bottom-eaters, so sinking food is a must, especially in a community tank shared with top feeders. Give flake food daily and an algae wafer every other day. Offer bloodworms or brine shrimp once or twice a week.

Is a Chinese Algae Eater Right for You?

Chinese algae eaters are a fascinating fish with a lot of personality. That said, they’re not for everyone. Some people are surprised by the change in temperament and eating habits that occur as they mature.

Young Chinese algae eaters are happy to clean the algae from your tank and may leave their tank mates alone, but, as they age, they’re less likely to be satisfied eating algae and may become aggressive and territorial.

Still, with a big enough tank and the right setup, it’s entirely possible to have a community tank that features a Chinese algae eater. Just remember to keep a close eye on the water parameters and supplement their diet appropriately.

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