Caring For Your Freshwater
Perhaps you have freshwater shrimp, or are thinking about
purchasing freshwater shrimp, but need to know about their care. Freshwater
shrimp are quite undemanding little creatures that have few requirements.
It has been my experience that most freshwater shrimp species
prefer water with moderate hardness, and a pH of 6.8 to 8.0. For Asian shrimp
species, a lower pH can lead to stress and mortality. Macrobrachium shrimp from
Peru and Brasil may be better suited for lower pH waters, but that is
speculation on my part..
Mixing shrimp and fish can be, at best, a difficult proposition.
Many fishes will eat smaller shrimp, and even lager shrimp species may be forced
into hiding. Your best bet here is to mix smaller shrimp species in with
smaller, non-aggressive fishes such as the Least Livebearer (Heterandra
formosa), African flame barb (Barbus
jae), small tetras, and the like. Larger shrimp, such as Amano (Caridina
japonica) and the smaller Macrobrachium species (such as the Vietnam
blue) can be mixed in with larger fish such as swordtails, platys and the like.
Larger Macrobrachium species, like the red-spotted and red-claw, are best
kept in a tank of their own as they can capture and eat small to medium-sized
fishes (at worse) or mutilate fish (at best; see
http://www.frankmgreco.com//fishmutilationbyshrimp.pdf). Fishes to avoid would include non-dwarf barbs, cichlids (even dwarf
ones), and other large species. However, when it comes right down to it, shrimp
are best off kept in their own tank.
Mixing shrimp species, like mixing
fishes and shrimp, can be a difficult proposition. Generally speaking, smaller
species can be mixed with smaller species without too much worry about
predation. The main problem here is the possibility of cross-breeding. Shrimp
taxonomy is not well defined, and shrimp that may not look the same may be the
same species. For example, the cherry red shrimp and Taiwan pale blue shrimp are
the same species (Neocaridina denticulata sinensis var. red and Neocaridina denticulata sinensis,
respectively), and will interbreed. Bee shrimp and Crystal Red shrimp are also
the same species (Neocardina serrata
and Neocardina serrata var. crystal red),
and will interbreed. I don't know if different species will interbreed, but that
is a possibility.
When it comes to the long-arm species, there is a definite possibility of shrimp
predation. Long-arm shrimp (Macrobrachium spp.) may eat smaller shrimp
species and conspecifics.
As mentioned above, shrimp are really at their best when kept in
a species tank. Such a tank need not be large, and anything from a 2.5 gallon on
up will house dwarf shrimp comfortably. Larger shrimp species, of course, will
require larger quarters. Even Eclipse™ systems will work well*.
No matter what size tank you choose, the basic set-up is the same. I prefer to
use a fine sand as a substrate, although it is not essential as long a larger
pebbled gravel is avoided. Lots of driftwood and rockwork is also appreciated as
are live plants, especially Java moss.
The type of food your freshwater
shrimp will need depends upon the species. While it's safe to say that these
animals are omnivvorous, there are some special requirements. Shrimp of the
Caridina/Neocaridina group should have a diet high in greens (algae, frozen kale
or collard greens, Spirulina tablets, etc), as should Halocaridina rubra.
shrimp (Macrobrachium luzifugum),
being a substrate dweller, should be fed more of a meat-based diet (tablet foods are good for
this), although flake food is also readily taken. Larger Macrobrachium species
will feed upon frozen foods such as mysis or bloodworms (as will the
afore-mentioned shrimp). They may also catch and eat smaller fish. Atya shrimp
are generally filter feeders, and should be fed small particles suspended in the
water. Crushed flake, Cyclop-Eeze™ and enriched Artemia nauplii are readily
taken. But when it comes right down to it, experiment. Try different types of
foods. The better the variety, the healthier the shrimp.
If you are looking for some easy to
breed shrimp species, the Neocaridina group is for you. All produce fully formed
young that are miniature versions of the adults. Macrobrachium luzifugum
also falls into this category, as do the Chocolate shrimp (Macrobrachium
sp.), red-spotted shrimp (Macrobrachium sp.) and yellow-banded shrimp (Macrobrachium sp.).
For other Macrobrachium species, Atya gabonensis, and the Amano
shrimp (Caridina japonica), brackish water is required for larval
development, making these shrimp more difficult to rear than other species.
Feeding Larval Shrimp
If you want to take a shot at
raising shrimp with small larvae, you will need to raise food for them. As for
culture systems, there are two basic approaches you can take. The first approach
is single batch culture which actually works pretty well for small spawns as
soon as you identify the first larval food source. The second approach,
recirculating bath, works well for larger spawns over longer larval cycles where
repetitive water changes become somewhat impractical. For the single batch
culture, you can use one gallon glass tea jars partially immersed in heated
water inside a twenty gallon-long aquarium. Five jars per 20-long if memory
serves me correctly. Each jar can be a separate spawn or a separate feeding
regime until you work out the nutritional needs for your desired species. To
start off, place the larvae into enough water so that their concentration is 50
larvae/liter of water in the tea jars (you can go above 100 later if things work
well). Place a submersible heater in the water (approx. 5 inches) in the 20
gallon tank. Set the temperature to your best guess as to the required
temperature for your species. This method calls for 50-75% daily water exchanges
in each jar so pre-heated conditioned water needs to be on hand daily as well as
appropriate larval feeds (i.e., phytoplankton, Artemia, Daphnia, and rotifers).
For longer larval development periods or when excessive water loss would occur
from daily changes (more a problem for marine and brackish tanks) use the
recirculating method. You can use a 5 gallon bucket for the culture vessel.
Place a bulkhead fitting at the base of the bucket and a standpipe with a series
of fitted nitex screen sleeves (80 microns, 120 microns, 180 microns, and 300
microns). These are just recommended sizes, they are not carved in stone. Place
the bucket above a column of BioBalls, Biospheres, etc... that empty into a
large plastic wash-tub (available at K-mart if you hurry before they go out of
business). Use a small submersible pump to pump water from the reservoir back up
to the culture bucket. The air should be added by a weighted or fitted ring
around the inside base of the bucket to allow continual gentle mixing. Above the
BioBalls a little floss should be used. Do not use to fine a grade of floss, you
do not want to remove most live feeds form the water. Place your heater in the
reservoir on bottom. I have used both types of systems successfully with several
species. Large commercial marine shrimp hatcheries producing 30 to 50 million
post larvae per month actually use a vastly upscale version of the first method.
* When using Eclipse™ systems to house shrimp, it is advisable
to wrap a piece of nylon window screen around the intake strainer. Failure to do
this may result in smaller shrimp (including babies) getting sucked into the
Copyright 2004 by Frank M.