Can 2 algae eaters live together?

Quick Answer

Yes, in most cases 2 algae eaters can live together peacefully in the same aquarium provided it is large enough and there are sufficient hiding places and food. Certain species like Siamese algae eaters and otocinclus catfish do especially well in groups. However, some care should be taken when mixing different algae eater species as they may be aggressive toward each other. Providing plenty of plant cover and driftwood helps diffuse tension.

Do algae eaters get lonely?

Most species of algae eaters are schooling fish that prefer to live in groups in the wild. Keeping just one algae eater in an aquarium can cause stress and anxiety due to loneliness. Having 2 or more algae eaters allows them to exhibit their natural schooling behavior which is important for their health and wellbeing. Some good options for algae eaters that should be kept in groups include:

– Otocinclus catfish: A peaceful community fish that should be kept in schools of 6 or more. They have a subtle brown coloration and grow to about 2 inches long. Otocinclus thrive when kept in groups as they are very social.

– Bristlenose pleco: A relatively small pleco species that reaches 3-5 inches. Bristlenose plecos are most comfortable when kept in pairs or trios as they can become reclusive if alone.

– Siamese algae eater: An active fish that grows to 6 inches long. Siamese algae eaters naturally live in large schools in the wild so they do best in groups of 5 or more.

– Clown pleco: A colorful suckermouth catfish that only grows to around 3 inches. They are active and entertaining when kept in small schools.

So in summary, most algae eaters are highly social and are best maintained in groups rather than singly. Keeping 2 algae eaters together allows them to exhibit their natural behaviors.

Ideal tank size for 2 algae eaters

When housing 2 algae eating fish, the ideal aquarium size depends on the species. Some general guidelines include:

– Small species like otocinclus catfish: Minimum 20 gallon tank

– Medium sized species like bristlenose pleco: 30 gallon tank

– Larger species like Siamese algae eater: 55+ gallon tank

Bigger is always better when it comes to aquariums. A larger tank dilutes waste buildup, provides more room to create territories, and allows for better water parameters. Aim for at least 20 gallons per algae eater as a starting point. Make sure any tank decor like rocks and driftwood provide ample hiding spots and line of sight breaks to diffuse aggression.

If housing multiple algae eating species together, go even bigger on the tank size. A good rule of thumb is an extra 10 gallons per additional algae eater species in the tank. For example, keeping 3 otocinclus and 2 bristlenose plecos together would need around a 50 gallon tank minimum (20 gallons for the otos + 30 gallons for the plecos). This allows each species to claim their own space and reduce conflict.

Best tank mates for algae eating fish

When selecting tank mates for algae eaters, choose peaceful community fish that occupy different areas of the tank. Some great options include:

– Small tetras like neon, cardinal, ember tetras
– Rasboras such as harlequin and lambchop rasboras
– Corydoras catfish
– Hatchetfish
– Dwarf gouramis
– Mollies and platies
– Danios like zebra danio
– Kuhli loaches

Avoid notoriously aggressive fish like tiger barbs, convict cichlids, jack dempseys, oscars, and red tailed sharks. Stick to docile community species no bigger than your algae eaters. Bottom dwellers like loaches and catfish make great tank mates as they share similar water parameter needs but don’t directly compete over resources.

You can also add shrimp and snails to help clean up extra algae and provide natural food sources. Just be cautious adding shrimp with larger algae eating species that may view them as food!

Signs of stress and aggression

Even in ideal conditions, there is always a small chance algae eaters may not get along. Watch for these signs of stress or aggression:

– Hiding frequently and avoiding tankmates
– Clamped fins or loss of color
– Skittish behavior when approached
– Damaged fins or tails
– Chasing or nipping behaviors
– Fighting over territory or resources

If any bullying or persistent harassment is observed, separate aggressors immediately. Try rearranging decor and tankmates to disrupt established territories. Adding more plants, caves, and driftwood can also help diffuse tensions long term by providing visual barriers and hiding spots.

Sometimes an algae eater might become suddenly aggressive even in a formerly peaceful community tank. This is usually a sign of stress or illness, in which case inspect water parameters, diet, and the overall tank environment to identify and correct any issues. Performing small frequent water changes can help reduce aggression issues in algae eaters and community tanks in general.

Feeding algae eaters together

When housing multiple algae eaters, ensure there is enough food for everyone. Algae alone is typically not enough to sustain them. Offer a varied herbivore diet consisting of:

– Sinking algae wafers and pellets
– Blanchued vegetables like zucchini, spinach, cucumber
– Driftwood, cholla wood to rasp on for fiber
– Quality flake and pellet foods for bottom feeders

Feed in different locations of the tank to prevent competition. Scatter foods like veggie clips on rocks or wood. Position algae wafers on opposite sides. Offer night feeding for nocturnal pleco species. Adding shrimp and snails helps supplement their diet between feedings.

Carefully monitor growth rates and body conditions. If any fish appears underweight or outcompeted at feeding times, you may need to separate it. Target feed shy individuals to ensure everyone is getting their fair share. An overfed tank means there is enough food for even bottom of the pecking order fish.

Algae eater species that go well together

Certain algae eating species coexist more harmoniously together. Some compatible pairings include:

– Otocinclus and bristlenose pleco: Both small peaceful fish with different feeding behaviors. Otos graze on smooth surfaces while plecos rasp on driftwood.

– Siamese algae eater and nerite snails: Active SAEs zip around the tank while nerites slowly plod along. Nerites help control leftover algae.

– Bristlenose and clown plecos: Clown plecos dwell on open bottom areas while bristlenose stick to wood. Clowns are peaceful toward other bottom feeders.

– Farlowella and twig catfish: These thin wood grazing species don’t compete for food due to different mouth positions. Twigs eat horizontally while farlowella scrape vertically.

– Common pleco and hillstream loaches: Hillstreams occupy the tank bottom and surfaces while common plecos focus on driftwood and glass. Both appreciate highly oxygenated water.

In general, avoid combining territorial bottom dwellers like bulldog plecos or babaulti cichlids that may compete over tank space. Shy and slow moving species also don’t mix well with boisterous fish.

Algae eater species to avoid housing together

Certain combinations of algae eaters are more prone to conflict. Avoid housing:

– Common plecos together: Large and territorial, especially males.

– Crossocheilus (Siamese algae eater) with Trichogaster (gourami): SAEs may fin nip slower moving gouramis.

– Chinese algae eaters with docile fish: Aggressive and may latch onto slime coats of other fish.

– Cichlids like keyholes with passive catfish: Liable to intimidate bottom dwellers.

– Turtles with fish: May bite or injure tankmates.

– Crayfish with any fish: Very predatory and likely to attack fish.

In general, avoid mixing aggressive species from similar habitats, different continents, or with very different swimming speeds and temperaments. Use caution when introducing new algae eaters to an established community, and have backup tanks available to separate any problem animals.

Typical algae eater behavior

When provided good conditions, most algae eating fish display peaceful community behaviors including:

– Schooling tightly in small groups of the same species. Otocinclus, Siamese algae eaters, and many catfish swim closely together.

– Foraging primarily at night. Nocturnal pleco and catfish species become active after lights out. Diurnal algae eaters graze during the day.

– Picking at algae covered surfaces. Grazing fish like otocinclus and farlowella rasp at plant leaves, glass, and decorations.

– Clinging to smooth surfaces. Plecos, otocinclus, Garra species, and hillstream loaches all exhibit suckermouth behavior.

– Rucking on wood. Driftwood grazers like plecos and twig catfish chew on submerged logs to consume film algae and aufwuchs.

– Burrowing in the substrate. Some bottom dwellers like clown and kuhli loaches sift and dig through the aquarium gravel hunting food.

– Avoiding fights. Most algae eaters are peaceful toward tankmates if provided sufficient space and food. Aggression usually reflects poor habitat.

Observe your algae eating species daily to learn their normal routines and behaviors. This makes it easier to notice any signs of stress or problematic aggression that may require intervention.

Troubleshooting algae eater aggression

If your algae eating fish become aggressive, try these troubleshooting steps:

1. Isolate aggressors into a quarantine tank to protect other fish.

2. Review tank size – increase gallons if undersized for inhabitants.

3. Add more hiding places and sight breaks like plants, rock caves, driftwood.

4. Rearrange decor to disrupt established territories and diffuse tension.

5. Perform partial water changes and test water parameters. Correct any issues.

6. Treat infections, parasites that may be stressing fish. Add aquarium salt.

7. Feed more to reduce competition. target feed bullied individuals.

8. Increase frequency of vegetable meals to keep grazers satisfied.

9. Add more herbivores to spread aggression and create larger schools.

10. As a last resort, rehome excess aggressors or victims if bullying persists.

Getting algae eaters back into a peaceful routine requires addressing the underlying issues driving the aggression. Lack of space, poor water quality, not enough food, and insufficient shelters tend to precipitate fighting. Correcting these husbandry issues can usually resolve abnormal aggression.


In most cases, keeping 2 algae eating fish together works well provided they are given an adequately sized tank and compatible tankmates. Species like otocinclus, bristlenose plecos and Siamese algae eaters thrive when maintained in small groups rather than solo. Avoid territorial bottom dwellers and ensure sufficient plant cover and driftwood is available to prevent disputes. With proper feeding and water conditions, algae eaters can coexist harmoniously together in a peaceful community aquarium. Pay attention to any signs of aggression or bullying and be prepared to separate offenders as needed. Ultimately selecting compatible species and providing a natural, stimulating habitat are key to success in housing multiple algae eating fish.

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