Amano Shrimp Care: Size, Diet, Breeding and the Caridina Japonica Name

Quick answer: The Amano shrimp (Caridina multidentata, sold for years as Caridina japonica) is one of the best algae-grazing shrimp you can add to a freshwater tank. It’s hardy, peaceful and bigger than most aquarium shrimp, around 1 to 2 inches, and it spends all day picking soft algae, biofilm and leftover food off plants and decor. Keep a small group in a mature, cycled tank of 10 gallons or more, feed them a little when algae runs low, and never use anything containing copper. The one thing most people get wrong: Amanos won’t breed in a normal tank. Females carry eggs, but the larvae need saltwater to survive.

Amano shrimp at a glance

Amano shrimp vs cherry shrimp vs bamboo shrimp: which one do you actually want?

These three are the most common “cleanup crew” shrimp, and they do very different jobs.

Here’s the honest part most care guides skip. Amanos are great grazers, but they won’t fix an algae outbreak on their own. They clear soft green algae, hair algae and biofilm, and they help keep a balanced tank clean. Tough algae like black beard algae is a different story: they may pick at it now and then, but they don’t clear it reliably. If algae is out of control, fix the cause first, usually too much light or too many nutrients, and use Amanos to keep it in check. Our bamboo shrimp guide covers why that species needs flow and filtered food instead.

Caridina japonica, multidentata or Yamato: are they the same shrimp?

Yes. Caridina japonica was the name used in the hobby for decades, and a 2006 study placed the species under Caridina multidentata, the name scientists use today. Stores still use both. “Yamato shrimp” and “Yamato numa ebi” are the Japanese names for the same animal.

It’s called the Amano shrimp after Takashi Amano, the Japanese aquascaper who brought it into the hobby in the early 1980s as an algae eater for his planted tanks.

Be careful with labels like “Australian Amano.” That’s usually Caridina typus, a smaller, different species. Color names like “sun orange” or “lemon yellow” Amano are trade names, so ask for the scientific name if you want a true Amano. Amanos also change tint a little with diet, mood and background.

How to identify and sex Amano shrimp

Amanos are clear to gray-brown with a line of small reddish-brown dots or dashes along each side, and a faint stripe down the back. They have a slightly arched body and are noticeably bigger than a cherry shrimp.

Setting up a tank for Amano shrimp

Tank size. 10 gallons is the minimum for a small group. A planted 20 gallon is better, with more surfaces to graze.

A mature tank. Add Amanos to a tank that’s been running for at least a month or two. New tanks have little biofilm to eat and less stable water. If you’re starting from scratch, see our fish tank setup guide and cycling guide first.

Plants and wood. Live plants, moss and driftwood give them both food and cover. They love grazing the biofilm on new wood, and our white fuzz guide explains why Amanos are the best at clearing it.

Filter guard. Fit a sponge over the filter intake. Young or small Amanos can get pulled in.

A tight lid. Amanos are escape artists, especially in a new tank or after a big water change. Cover gaps around cables and filters.

How to add Amano shrimp to your tank

Shrimp handle sudden water changes much worse than fish, so acclimate them slowly. Float the bag for about 15 to 20 minutes to match the temperature, then move the shrimp and their water into a clean cup or container. Run a length of airline tubing from the tank into the cup with a small valve or a loose knot, so tank water drips in slowly. Over about an hour the water volume should roughly double. Then net the shrimp into the tank and throw away the cup water.

Here’s that drip method in a short clip from my own tank. These are orange cherry shrimp, not Amanos, but the steps are exactly the same: bag floated first, then a slow drip of tank water through airline tubing into the cup.

Water parameters

Amanos are among the hardiest aquarium shrimp. Aim for 65 to 80 F (18 to 27 C), a pH around 6.5 to 7.5, and moderately soft to moderately hard water. Ammonia and nitrite must stay at zero. Warmer water makes them more active but can shorten their lifespan, so there’s no need to run the tank hot.

Stability matters more than exact numbers. Do regular, moderate water changes with conditioned water at a similar temperature, rather than rare, huge ones.

The one hard rule: no copper. Copper is toxic to shrimp and snails. Check the label on every fish medication, algae treatment and plant fertilizer before it goes in.

What do Amano shrimp eat?

In a mature tank, Amanos feed themselves most of the time on algae, biofilm, leftover fish food and dead plant matter. In a very clean tank, or with a big group, give them a little extra a few times a week: algae wafers, shrimp pellets, or blanched zucchini or spinach.

Don’t overfeed. Uneaten food rots and feeds the algae you got them for. If they’re swarming the fish food every time, they’re getting enough. Hungry Amanos can sometimes nibble soft new plant growth, which is another reason to keep them fed.

Amano shrimp tank mates

Amanos are peaceful and do well with small, calm fish, other shrimp and snails. Good companions include honey gouramis, pygmy corydoras, small tetras and rasboras, cherry shrimp, and nerite snails. They also share a tank well with a bristlenose pleco.

Avoid fish big enough to eat them, like large cichlids, goldfish, big gouramis and adult angelfish. Amanos are bold at feeding time and will happily snatch food from slow fish, but they don’t hurt them.

Breeding Amano shrimp

You’ll often see a female carrying a clutch of dark green eggs under her tail, but in a freshwater tank those eggs won’t turn into baby shrimp. Amanos are amphidromous: in the wild, the larvae drift downstream into the sea, develop in saltwater, and the young shrimp then migrate back into rivers.

Breeding them at home is possible, but it takes a separate saltwater setup, microalgae feeding and careful salinity changes. For a shrimp that breeds on its own, keep cherry shrimp alongside your Amanos.

Common Amano shrimp problems

A white shrimp that isn’t moving. Check whether it’s a shed shell first. Amanos molt regularly, and the empty clear shell looks like a dead shrimp. A real dead Amano usually turns pinkish or milky white and doesn’t hold its shape well.

Shrimp dying after a water change. Usually a sudden change in temperature, hardness or pH, or tap water that wasn’t conditioned. Change less water at a time and match the temperature.

Failed molts. A shrimp stuck halfway out of its old shell usually points to unstable water or a sudden mineral change. Keep water changes moderate and regular.

Shrimp hiding all the time. Normal for the first week or so. If it continues, check for large fish that might be bullying them.

Shrimp climbing out. Often poor water quality or a brand-new tank. Test your water and cover the gaps.

Shrimp swimming frantically. Can be a sign of a problem in the water, but males also swim around after a female molts. If it’s every shrimp at once, test your water right away.

Found an empty shell? Read our shrimp molting guide to check whether it’s a molt or a dead shrimp.

Not eating the algae. They may be getting fed too much, or the algae is a type they don’t like. Cut back on extra food and see our algae eater guide for other options.

FAQ

Is Caridina japonica the same as the Amano shrimp?

Yes. Caridina japonica is the older name for the Amano shrimp, which is now classified as Caridina multidentata. Care is exactly the same.

How big do Amano shrimp get?

About 1 to 2 inches (2.5 to 5 cm). Females are larger than males.

How long do Amano shrimp live?

Usually 2 to 3 years in a stable tank, and sometimes longer.

Can Amano shrimp breed in freshwater?

No. Females carry eggs in freshwater, but the larvae need saltwater to develop and die within a few days without it.

How many Amano shrimp should I keep?

At least three, and roughly one per 2 gallons, adjusted for how much algae and biofilm your tank has.

What is the difference between Yamato and Amano shrimp?

There’s no difference. Yamato shrimp is the Japanese name for the Amano shrimp.

Where are Amano shrimp native to?

Japan and Taiwan, where they live in rivers and streams that connect to the sea.