Aquaponics Library


Freshwater Shrimp to control algae

Freshwater shrimp in the genera Palaemonetes are excellent scavengers
and do eat algae. The two strickly freshwater inhabitants are P.
kadiakensis and K. paludosus. Their westward distribution is limited to
the flood plains of the Mississippi River. In the southern parts of
U.S., they are found as far west as about San Antonio, TX.
There are also freshwater shrimp native to the U.S. in the genera
Macrobrachium. However, they can get large and do damage to a plant tank.

The use of freshwater shrimp as algae eaters and the state-of-the-art
for plant tanks in Japan.
In Japan, shrimps are commonly used to maintain the planted tanks.
A magazine says the use of shrimps is the biggest change in these
10 years in the planted-aquarium scene.
The combination of shrimps and otocinclus is the way which most books
recommend for beginners of plant tanks for controlling algae. (And,
optionally, Tetra Algae Kit for brue-green algae.)  Roughly,
otocinclus are for green or brown algae on the glass, rocks and
broader leaves, on the other hand, shrimps can handle brush/hair algae
and fine leaves like moss or riccia.  (I have no idea whether the
shrimps eat red algae, since I haven't figured out what the red algae
is.)  According to the books, they have preference for fish food
rather than algae.  So, overfeeding the fish can make the shrimps lazy
algae eaters.
There are 2 species of algae eating shrimps popular in Japan:
(1)Domestic ones (Yamato-numa-ebi i.e. Japanese-pond-shrimps)
   They grow to 5cm or so.  They are not tropical and likely die
   when the temp gets over 30C.  All the local aquarium shops I visit
   carry them.  They often hold eggs, but are hard to reproduce in most
   planted tanks since they need brackish water for breeding.
   They are supposed not to bear the pH under low 6.
(2)Bee shrimps
   They grow to 2cm or so.  They are from South-east Asia.
   Recently, they are not well-supplied since the flood damaged the
   farms (ponds) in the South-east Asia a while back.  They are born in
   the same shape as the parents, and easily reproduce in the planted
   aquariums if no enemies are there.
     I have been wondering why no one mentions the shrimps when
     somebody calls for help on an algae problem in rec.aquaria.
     Are shrimps rarely used as algae-eaters in the US?
Yamato-numa-ebi (Japanese pond shrimp): Caridina japonica
  temp 15-28C, pH neutral, size 5cm (typically sold 3cm)
Bee shrimp                            : Atydae sp.
  temp 20-28C, pH neutral, size 2cm
Another domestic shrimp which is sold as algae eater is:
Minami-numa-ebi (Southern pond shrimp): Neocaridina denticulata
  temp 15-28C, pH neutral, size 3-4cm
I found the following table about rating algae-eaters in a magazine. (Note
that most article in the magazines are author's personal opinion.)
|Algae-eaters       | brown algae | string-type | lawn-type |
|Ishimaki-gai snail |      1      |      1      |     3     |  0 doesn't
|Golden Apple Snail |      1      |      2      |     3     |  |   eat
|Otocinclus         |      3      |      0      |     1     |  1
|Siamese Algae Eater|      1      |      2      |     1     |  |
|Farlowella         |      3      |      0      |     1     |  2 eats
|Pencilfish         |      0      |      1      |     0     |  |
|Shrimps            |      0      |      2      |     0     |  3 eats well

Various freshwater shrimps imported from South East Asia as novelties.
Forget about latin names...I've tried to classify
prawns for marine surveys, and it's TOUGH. Only one is really easy,
Macrobranchus. This is a very large shrimp, about 10cm long or more, and
the males have very large pincers. There is also a frequently imported
filter feeding shrimp, which has four modified arms it uses to feed,
which look like tiny, hairy, fans. No idea what it is called, but seems
quite hardy and grows quickly.
Most marine shrimps have planktonic larvae, and are very difficult to
raise. Some marine and estuarine shrimps carry the eggs around, but the
larvae still hatch as planktonic animals, not miniature shrimps. True
freshwater shrimps raise the babies beneath the legs until they are able
to fend for themselves. These are not planktonic larvae, but are very
small and difficult to raise. Try putting the brooding parent into a
breeding trap. When the eggs hatch they will need minute algae, pond
water would be ideal. Basically, treat them as if you were raising
Artemia (brine shrimp), in an algae rich medium with gentle aeration.
Liquid invertebrate food would also be useful.

japonica Stocking

Amano suggests (2 shrimps : 1 gallon).
So 5 seems to be about the right number of shrimp for a 2.5 gallon tank.
Keeping too many of them in the absence of an alternative food source will
force them to eat your plants. Keeping too few may increase the likelihood of
an algae outbreak.
 Is there alot of variation in the coloring/marking of C. japonica shrimp?
Yes. I have fifty of them in a 29 gallon tank. They vary considerably in
coloration and transparency. These qualities tend to change with age. The
yellow line grows more pronounced with age. Moreover, the intensity and size
of the spots on the side of the shrimp vary considerably. I have shrimp with
spots so faint that they are almost undetectable and others with large,
pronounced spots in-line along the length of the shrimp's tail.
 I love these guys! They eat everything from detritus to
BBA. They are worth every penny. And when you buy fifty of them, those
pennies add up! :)

Freshwater Inverts

You might try Carolina Biological Supply ( or other
scientific or educational supply companies.  I haven't bought from
Carolina Biological, but they are a well-established firm.  I checked with
them this morning and their online catalog lists a variety of freshwater
I have ordered ghost shrimp, planaries and protozoans from Carolina Biological Supply
several times in the past. They have an excellent service and the live stock has always
arrived fresh and healthy. I personally recommend it. They also have a lot of laboratory
utensils that are very useful to this hobby.