Amano Shrimp
Invertebrates
The champion algae eater that clears a tank and never overruns it!
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🤓 Did you know? Amano shrimp can't reproduce in a home freshwater aquarium at all. Females carry eggs and release free-swimming larvae just fine, but those larvae need brackish to full-strength salt water to survive past their first few hours of life, then must be raised through several weeks of saltwater development before metamorphosing into juveniles that can return to fresh water. Because of this, almost every Amano shrimp sold in stores today is wild-caught, not captive-bred.
🗓️ The first week
The numbers a new owner needs in the first week, each from the article it links to. Rows with no link come from the encyclopedia.
- Tank size
- A 10-gallon is the practical minimum. Surviving in 5 gallons is not the same as having room to forage.Setup guide →
- How many
- One per 2 gallons to start, five in a 10-gallon. A tank fighting an algae outbreak carries more, but more shrimp on the same algae only means it runs out sooner.Setup guide →
- Temperature
- 64 to 82°F tolerated, and shrimp kept in the upper 60s to mid-70s live longer, since warm water speeds metabolism. Set the heater conservatively.Setup guide →
- Water chemistry
- pH 6.0 to 7.5, KH 2 to 8, and GH 4 to 15 with 6 to 8 dGH the usual target. Too little hardness and a new shell cannot harden; too much and the old one is too rigid to break out of. A conditioner on every drop of tap water.Setup guide →
- With cherry shrimp
- Usually fine, with the caveat that amanos are considerably bigger and outcompete them at feeding time.Enrichment guide →
- The lid
- Not optional. They climb out through a gap the width of a cord, especially in the first days, and turn up dried out in the morning.Setup guide →
- Filter intake, not flow
- A sponge filter because a standard intake pulls in a freshly molted shrimp. It is an intake-safety choice, not a flow limit: this is a fast-stream animal.Setup guide →
- Copper
- Shrimp blood runs on copper, which is why free copper is so disproportionately dangerous. Common copper fish medications and some fertilizers run 0.15 to 0.20 mg/L, inside the range where a 2025 study found shrimp harmed.Health guide →
- What they eat
- Hair algae, thread algae, and black beard algae, which most fish and snails leave. Not flat green spot algae, and not cyanobacteria.Feeding guide →
- Algae runs out
- It is a starting supply, not a renewable one, and a group clears it faster than expected. Supplementing is part of the diet, not a fallback; a shrimp climbing the glass and decor searching is hungry.Feeding guide →
- How often to feed
- A small amount every couple of days, leftovers out after a few hours, so they stay motivated to work the tank. In more than one spot: a single wafer becomes one shrimp's wafer.Feeding guide →
- Drip acclimation
- One to two hours at one to two drops per second, three or four hours if the water gap is large. Osmotic shock is a known trigger for failed molts.Handling guide →
- Quarantine
- Two to four weeks in a separate cycled tank. Virtually every amano sold is wild-caught, so hitchhikers and stress get time to show.Handling guide →
- Molting
- A failed molt is the shell splitting all the way around the body instead of at the head, usually from GH and KH swinging around a water change or a diet short on calcium. There is no treatment once it starts.Health guide →
- Water changes
- Small and steady, since swings in hardness around a change trigger failed molts. Test nitrate rather than changing by the calendar.Aquarium Water Changes →
- Budget
- $5 to $12 each, cheaper in a group. Core equipment roughly $60 to $150.Cost guide →
- Lifespan
- 2 to 3 years, longer at the cool end of the range.Cost guide →
- Adult size
- Up to about 2 inches (5 cm); large for a dwarf shrimp.
🚨 Emergency card
Test the water first, then act on these today. No vet treats a shrimp; prevention is the whole plan.
- A shell split all the way around the body instead of opening at the head: a failed molt, with no treatment once it starts
- A whole group dying suddenly with no warning: ask what changed in the water, a copper exposure, an ammonia or pH swing, a rushed water change
- Shrimp climbing the glass and decor in constant search: hunger, and the algae has run out
Check the label of any fish medication or fertilizer before it goes near the tank: the copper doses considered safe for fish sit inside the range that harms shrimp.
📰 Where to go next
How Much Does Amano Shrimp Ownership Really Cost?
$5 to $12 a shrimp with real listings behind it, the $60 to $150 setup, and why a cooler tank is the cheaper one across a shrimp's life.
Amano Shrimp Tank Setup: Minimal Bioload, Real Current, and a Lid That Actually Seals
The 10-gallon minimum and one shrimp per 2 gallons, general hardness as a molting input, a sponge filter for intake safety rather than calm water, and the lid.
Amano Shrimp Feeding: The Hobby's Best Algae Eater, With Real Limits
What the best algae eater in the hobby actually eats, the flat adhered algae it can't, and why a clean tank means supplementing before they starve.
How to Handle Amano Shrimp (Minimal Contact, Careful Acclimation)
Netting instead of hands, drip acclimation over one to two hours, and the quarantine a wild-caught animal earns.
Common Amano Shrimp Health Issues (And Why 'Disease' Usually Isn't the Right Word)
Failed molts and what causes them, the 2025 copper study and the doses that harm before they kill, and why eggs that never hatch are normal.
Amano Shrimp Enrichment: The Algae Runs Out and Nobody Notices
Grazing surface as the whole enrichment question, biofilm over bare glass, and somewhere soft to hide out a molt.
🛒 What to buy
Prices and the reasoning behind each item are in How Much Does Amano Shrimp Ownership Really Cost?.
❓ Frequently Asked Questions
Why is my amano shrimp carrying eggs that never hatch?
Because this species cannot complete its life cycle in freshwater. A female mates and carries fertilized eggs normally, and they even hatch into free-swimming larvae, but those larvae need brackish to marine water within their earliest stages to survive and develop. In a standard freshwater tank they die within days, and the whole cycle repeats with the next batch of eggs. It's completely normal, not a sign anything is wrong with your shrimp.
How sensitive are amano shrimp to copper?
Very sensitive, and it's backed by real research, not just hobby folklore. A 2025 study in the Journal of Crustacean Biology put the acute lethal copper threshold for this species at 1.15 mg/L, but found measurable sublethal harm, including a reduced ability to detect food odors, at concentrations well below that. Common copper-based fish medications and some plant fertilizers are formulated around roughly 0.15 to 0.20 mg/L, a level considered safe for treating fish parasites but squarely inside the range where shrimp show real harm.
What algae are amano shrimp good at eating?
Hair algae and thread algae are where they excel, and they'll take on black beard algae too, which most fish and snails leave completely alone. A well-established beard algae mat is still more than one animal can fully clear on its own.
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📰 Deep Dive
🦐 How Much Does Amano Shrimp Ownership Really Cost?
🦐 How to Handle Amano Shrimp (Minimal Contact, Careful Acclimation)
🦐 Common Amano Shrimp Health Issues (And Why 'Disease' Usually Isn't the Right Word)
🦐 Amano Shrimp Tank Setup: Minimal Bioload, Real Current, and a Lid That Actually Seals
🦐 Amano Shrimp Feeding: The Hobby's Best Algae Eater, With Real Limits
🦐 Amano Shrimp Enrichment: The Algae Runs Out and Nobody Notices
🩺 Health and More
🦠 How to Cycle a Fish Tank, Start to Finish: Fishless and Fish-In
🧽 Aquarium Filtration: How It Actually Works and How to Maintain It
🪣 Aquarium Water Changes: How Much, How Often, and What the Number Is For
🐟 Aquarium Stocking and Tankmates: How Many Fish, and Which Ones Go Together
🦐 Shrimp Molting: What a Normal Molt Looks Like, and the White Ring That Means It Failed
🧪 Freshwater pH, GH, and KH: Why Chasing a Number Backfires
🤩 Fun Facts
🦐 Needs Salt Water to Be Born, Dies From It as an Adult
Amano shrimp larvae cannot survive unless they reach brackish or marine water within their first days of life, yet the adults are the opposite, even a small, accidental dose of salt can kill a mature amano shrimp outright. The same animal that's biologically obligated to spend part of its life cycle in salt water would die if you tried to acclimate it into a saltwater tank as an adult.