Algae Control 5 min read

The Ultimate Algae Eater Face‑Off: Otocinclus vs. Nerite vs. SAE

By The Aquarium Calculators ·

Otocinclus, Nerite snails, and Siamese Algae Eaters each excel at eating different types of algae. Learn which one is the ultimate cleanup crew for your aquarium.

A Siamese Algae Eater swimming near a tank wall with algae

Quick Answer

Otocinclus catfish, Nerite snails, and Siamese Algae Eaters each target different algae types with varying efficiency. Otocinclus excel at removing soft green algae and diatoms from plant leaves, Nerites control green spot algae on glass, and SAEs are the only species that reliably consume Black Beard Algae. A cleanup crew of 1 Otocinclus per 10 gallons is a standard stocking benchmark.

When algae strikes, a cleanup crew is often your first line of defense. The three most popular and effective algae eaters are the Otocinclus catfish, Nerite snail, and Siamese Algae Eater (SAE). But each has specific strengths and weaknesses. Here's how to choose the right one for your tank.

Otocinclus Catfish: The Gentle Glass Cleaner

Appearance: Small (1.5-2 inches), slender, with a brown/black horizontal stripe.

Best For: Soft green algae and diatoms (brown algae) on glass, plant leaves, and smooth surfaces.

Pros: Extremely peaceful; safe with all tank mates; very efficient at cleaning soft algae; fun to watch in a school.

Cons: Highly sensitive to poor water quality; must be kept in groups (5+); very sensitive to nitrates; difficult to feed supplemental food; may starve once algae is gone.

Tank size: Minimum 20 gallons for a group.

Nerite Snail: The Cleanup Tank

Appearance: Small (0.5-1 inch), hardy shell with various patterns (zebra, tiger, olive).

Best For: Everywhere—glass, rocks, driftwood, plant leaves. They eat most algae types, including tough green spot algae and diatoms.

Pros: Invertebrate—doesn't add to bioload; 100% algae diet; cannot reproduce in freshwater; extremely peaceful; very hardy.

Cons: Females will lay unsightly white eggs on driftwood and decorations that won't hatch; can escape from uncovered tanks; may be eaten by loaches, cichlids, and goldfish.

Tank size: Any size; 1 snail per 5 gallons is a good rule of thumb.

Siamese Algae Eater (SAE): The Beast Slayer

Appearance: Larger (5-6 inches), silvery body with a bold black horizontal stripe.

Best For: Stubborn algae, especially the dreaded Black Beard Algae (BBA) and hair algae, which most other algae eaters ignore.

Pros: Eats problem algae; very active and entertaining; generally peaceful; can be kept in a group.

Cons: Grows large (needs a 55+ gallon tank); may become lazy and prefer prepared food as it ages; often confused with the aggressive and useless Chinese Algae Eater (CAE).

Tank size: Minimum 40-55 gallons for an adult.

Which Algae Eater is Right for You?

Best for a Nano Tank: Nerite Snail — hands down. They are small, efficient, and won't overstock your tiny aquarium.

Best for a Community Tank: Otocinclus Catfish — their peaceful nature and small size make them perfect for a planted community tank. Just be sure to get a group of at least 5-6.

Best for Black Beard Algae (BBA): Siamese Algae Eater (SAE) — is one of the few fish that truly eats it. Make sure you're buying the true SAE (Crossocheilus oblongus).

The Dream Team Cleanup Crew

Most successful planted tanks use a combination of these algae eaters. A group of otocinclus will handle the soft green algae on plant leaves and glass, a few nerite snails will polish the hardscape, and an SAE (in a large tank) will keep the stubborn hair and black beard algae at bay. This multi‑pronged approach, combined with proper lighting and nutrient balance, will keep your tank looking pristine.

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Frequently Asked Questions

Do Siamese Algae Eaters eat Black Beard Algae?
Yes, true Siamese Algae Eaters (Crossocheilus oblongus) are one of the few fish that actively eat tough black beard algae, especially when young.
Are Nerite snails safe for planted tanks?
Yes, Nerite snails are 100% safe for plants. They clean algae off leaves and glass surfaces without eating or damaging live vegetation structures.
How many Otocinclus should be kept together?
Otocinclus are shoaling fish and should be kept in groups of at least 4 to 6. They require an established tank with plenty of natural algae to survive.
Will these algae eaters eat fish food if there is no algae?
Yes. Siamese Algae Eaters and Otocinclus will readily eat flake food, algae wafers, and shrimp pellets if they run out of natural algae. Nerite snails, however, are strict algae grazers and may starve if the aquarium doesn't produce enough natural biofilm or green spot algae.