Amano shrimp

Quick facts

Adult size

5 cm

Lifespan

can live up to 3 years; captive average 2-3 years

Tank zone

all

Temperament

peaceful

Difficulty

beginner

Water parameters

Temperature

18–27°C

pH

6.5 to 7.5

Hardness

6 to 15 dGH

Tank requirements

Minimum volume

40 L

Minimum length

45 cm

Flow

moderate

Lighting

moderate

Substrate

any

Driftwood

preferred

Hiding spots

needed

Lid

required - jumper

Feeding

Diet: herbivore, feeds primarily at the all.

Aggressive algae grazer that will clean a tank visibly within days of introduction. In a tank with limited algae, supplement with algae wafers, blanched vegetables, and commercial shrimp food. Amanos are bolder and more food-motivated than cherry shrimp; they'll snatch food from the surface and carry it away. Don't underfeed in a clean tank or they'll go after weakened fish. A well-known behavior: amanos will try to steal food from fish and from each other, carrying pieces away and eating while running.

Vegetable matter required (algae wafers, blanched zucchini, spinach).

Compatibility

• Safe with all community fish. Large enough that most fish ignore them, unlike cherry shrimp.
• Will not eat healthy plants. May pick at dying leaves, which is beneficial.
• Can coexist with cherry shrimp, though amanos sometimes bully smaller shrimp away from food.
• Avoid keeping with large cichlids, puffers, or anything that actively hunts invertebrates.
• Copper is lethal. Check medications and fertilizers before dosing a tank with shrimp.

Habitat

Native to Japan, Taiwan, and parts of mainland Asia. Named after Takashi Amano, who popularized them in aquascaping in the 1990s for their algae-eating ability. Wild populations are amphidromous: adults live in freshwater streams, but larvae wash downstream to brackish estuaries to develop before migrating back upstream. This lifecycle is the reason they don't breed in freshwater aquariums (larvae die without saltwater). Larger than cherry shrimp at 4–5 cm, with a translucent gray-green body and rows of reddish-brown dots along the flanks. The best algae-eating shrimp available for freshwater tanks, particularly effective against hair algae and soft green algae that other shrimp and fish won't touch.

Breeding

Cannot breed in freshwater. Females carry eggs readily, but the larvae require brackish to full saltwater to survive. Hobbyist breeding is possible but demanding: remove berried females to a separate brackish setup (15-35 ppt salinity) before the larvae hatch, raise the larvae on phytoplankton for 4-6 weeks, then gradually acclimate juveniles back to freshwater. Success rates are low even for experienced breeders. All amano shrimp in the trade are wild-caught from Japanese and Taiwanese rivers, which raises long-term sustainability questions as demand grows.

Common problems

Climbing out of the tank is the most common problem. Amanos are escape artists and will climb airline tubing, filter intakes, and any surface that extends above the waterline. A tight-fitting lid with no gaps is mandatory. Failed molts from mineral deficiency (same as cherry shrimp; maintain GH 6-8). New arrivals sometimes die within the first week from drip-acclimation failures; amanos are more sensitive to parameter swings than cherry shrimp. Acclimate slowly over 2+ hours. In a heavily planted tank with CO2 injection, amanos may be stressed by low pH during the photoperiod; keep pH above 6.0.

Bioload

Bioload coefficient: 0.2 (5 cm but light-feeding algae grazer; effective bioload is roughly twice a cherry shrimp).

Bioload coefficients are calibrated against the neon tetra as the anchor (1.0). See the methodology page for the formula and how each value was derived.

Further reading

• Algae: what kind you have and how to fix it
• Stocking ideas by tank size