Photo: sannse · CC BY-SA 3.0
Freshwater · Beginner · 20+ gal
Caridina multidentata
By Fishy Dave
Amano shrimp (Caridina multidentata) are beginner invertebrates in a cycled, copper-free tank. Plan a crew of 3–6 in a 20-gallon planted setup. Adults reach about 1.5–2 inches. Feed biofilm plus wafers. Do not expect a freshwater breeding colony.
| Water type | Freshwater |
|---|---|
| Care level | Beginner |
| Minimum tank | 20 gallons |
| Temperament | Peaceful algae grazers. A crew of 3–6 works a planted 20. Skip large cichlids and goldfish that treat a 2-inch shrimp as food. |
| Diet | Biofilm and soft algae first. In a spotless tank they starve unless you add sinking veg wafers or blanched greens on a schedule. They are hired algae help, not a water-change replacement. |
| Temperature | 65–80 °F |
| pH | 6.5–7.5 |
| Hardness / salinity | Soft to moderately hard. Stable, copper-free water matters more than chasing a perfect pH. They still molt, so bone-dry soft RO without remineralizing is a bad plan. |
Caridina multidentata is the Amano shrimp shops sell for algae. Adults land around 1.5 to 2 inches, larger and more mottled than cherry shrimp, with rows of dark dots along the flanks. One lonely shrimp cleans a corner. A crew of three to six actually works glass, wood, and plant leaves in a 20-gallon planted tank.
Twenty gallons is the honest floor for that useful crew, not a nano bowl with one shrimp on the bag. Temps roughly 65–80°F cover most community mixes. An adjustable heater holds that band in a cool room. Finish the cycle before you buy. Ammonia spikes kill shrimp as fast as they kill fish.
Soft green film and biofilm are the staple. A brand-new kit with crystal-clear glass has almost nothing for them. Let the tank run, grow plants, and leave some film on the glass and wood. When the glass goes clean, break off a sinking veg wafer or offer blanched zucchini, then pull leftovers after a few hours.
They are not janitors for overfeeding. Uneaten food and shrimp waste still need vacuuming and water changes. Copper meds, some plant fertilizers, and old copper plumbing kill them. Read labels and keep copper chemistry out of this tank.
Cherry shrimp breed in freshwater and build a colony. Amanos almost never produce babies that survive in a home freshwater tank. Their larvae need brackish conditions most hobbyists never set up. Buy the crew size you want and treat them as hired algae help, not a self-replacing population.
Gentle filtration suits them. A sponge filter or a baffled hang-on-back keeps flow soft and leaves biofilm on surfaces. Community tetras and rasboras are fine tank mates. Large cichlids and goldfish are not. Pair them with otos or a bristlenose if you want more grazing without stacking the same animal twice.
A few listings we would open for this species. Skip anything you already own that still works.
hygger sponge filter, small
Gentle flow that leaves biofilm on glass and wood instead of blasting every surface clean. Shrimp-safe foam intake for a 20 with a small Amano crew.
Needs an air pump, airline, and a check valve. Squeeze the sponge in old tank water only. Skip this if a baffled hang-on-back already holds ammonia at zero and the flow is soft.
See this listingTetra PlecoWafers, 3.03 oz
Sinking veg wafers fill the gap when the glass is clean. Break off a small piece a few times a week and pull what is left after a few hours.
Blanched zucchini still belongs in the rotation. Skip dumping a whole wafer into a lightly stocked 20. Uneaten food fouls the tank faster than it feeds shrimp.
See this listingCanton Aquatics Malaysian Driftwood
Wood and leaf litter grow the biofilm Amanos actually hunt. A real piece of Malaysian driftwood gives grazing surface that plastic décor does not.
Rinse and soak or boil before it goes in if you want less tea-stain on day one. Size the piece so the crew still has open floor. Skip resin wood as the only surface.
See this listingA crew of 3–6 in a planted 20-gallon does real algae work. One shrimp is mostly decoration. Plan bioload for the group you buy, because they will not breed you a replacement batch in freshwater.
Almost never with surviving babies. Females may carry eggs, but the larvae need brackish water. Cherry shrimp are the colony breeders. Amanos are the algae crew you repurchase if you lose them.
Use a 20-gallon for a useful crew of 3–6. Smaller tanks can hold one or two, but you lose the cleaning payoff and the tank is harder to keep stable and copper-free.
No. They graze soft algae and biofilm and still produce waste. Test, vacuum, and change water like any other stocked tank. Feed wafers when the glass is clean so they do not starve.
Next step
Plan on 20 gallons or more. Put your actual tank size into the stocking calculator and it shows what else can live alongside them.
Open the stocking calculatorBefore you buy
Keep your fishies swimming.
Freshwater · Beginner
Neocaridina davidi
Cherry shrimp (Neocaridina davidi) are beginner invertebrates if the tank is cycled and copper-free. A starter colony of 10+ needs about 5 gallons; 10 gallons is easier. They need minerals for molting, not a second fish-page clone.
Min. tank: 5 gal
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Otocinclus spp.
Otocinclus (Otocinclus spp., often O. vittatus in the trade mix) stay about 1.5–2 inches. A school of 6+ belongs in a 20-gallon that has been running months with algae and biofilm, not a new 10-gallon sucker hire.
Min. tank: 20 gal
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Bristlenose plecos (Ancistrus) stay about 4–6 inches. A 20-gallon long is the floor for one adult; 29–30 gallons is the comfortable home. They need driftwood and wafers. They are not a common pleco and not a janitor.
Min. tank: 20 gal
Care notes →
