Shrimp and snails are the go-to invertebrates that people think about when stocking a freshwater aquarium, but there are also some crabs that make great options. One such species is the
Thai micro crab (Limnopilos naiyanetri), a diminutive crab that has
only been found living among the roots of floating plants such as
water hyacinth in a single area of Thailand.
These crabs certainly live up to the “micro” in their name.
Their carapace (body) will reach a maximum size of about ½ inch
( 1 cm) across, and their thin, spindly legs will only span up to
about 1½ inches ( 4 cm). At first glance, they almost appear more
like underwater spiders than crabs.
Unlike more commonly seen freshwater crabs, Thai micro
crabs are fully aquatic and will stay underwater for their entire
lives. However, they
are quite adaptable
to different aquatic
people who have
kept Thai micro
crabs have done so
in relatively neutral
in the 70s F (low-
to mid-20s C), but
they have been kept
in both slightly acidic
and slightly alkaline
conditions. There hasn’t
been much success in
getting them to reliably
breed, so it’s possible
that their ideal water
parameters haven’t yet
been dialed in.
Thai micro crabs
are extremely peaceful
and won’t harm your
other tank inhabitants.
However, they also don’t have much in the way of defense mechanisms,
so you do need to be very careful about what tankmates you put with
them. With their small size and inability to defend themselves, it’s very
easy for them to become snacks for your fish.
While they live in the roots of floating plants in the wild, in the
aquarium they seem to be right at home living among almost any
plants you keep. They particularly seem to appreciate fairly dense
plants that provide them cover and a place to hide. These little crabs
are a particularly good option for planted nano tanks. They are
omnivorous and will scavenge food both from out of the substrate
and snagged from the water column. Treat them like a filter feeder,
providing food that has been thoroughly crushed up and that easily
breaks apart in the water.
impor t repor t
Michael Griffith has been keeping fish
for 15 years and started working in a
retail fish store in 2004. He is now the
Marketing Manager for Segrest Farms
and is focused on developing educational
materials to help both hobbyists and
retailers be better fishkeepers. Michael’s
fish interests include sustainability and
conservation, and he enjoys finding
what makes underrated species special.
He is currently working to add pages
and articles to www.segrestfarms.com,
and you can connect with him on any
of Segrest Farms’s social media pages.
Vampire Shrimp (Atyopsis gabonensis)
Thai Micro Crabs (Limnopilos naiyanetri )
In freshwater aquariums, most of the ornamental shrimp focus lies on one of three types of shrimp: the Neocaridina cherry shrimps, the Caridina crystal reds (as well as the various color
forms of both of those groups), and the algae-eating Amano shrimp.
These are especially popular in planted tanks. However, there are
some alternative shrimp available that are frequently overlooked.
One of the most interesting of these is Atyopsis gabonensis, the
Vampire shrimp are not very well studied. While they are
currently listed as being native to both West Africa (Senegal and the
Democratic Republic of the Congo) and South America (Venezuela
and Brazil), it’s very possible that these are in fact different species.
However, they are closely related to bamboo shrimp (A. moluccensis)
from Southeast Asia.
The most immediate difference between vampires and the more
commonly seen shrimp is their size. Vampire shrimp can grow to
about 6 inches ( 15 cm) in length, requiring a substantially larger
aquarium than the dwarf varieties. Like bamboo shrimp, they are
also filter feeders, requiring a somewhat different approach than you
might take with other shrimp. They prefer to sit in one spot in the
current, especially on top of a piece of driftwood, snatching food
particles as they float by.
While they can be fed tiny foods such as those available for feeding
fish fry or even finely crushed-up flakes, vampire shrimp will do
best when they’re kept in an aquarium that has been set up long
enough for a robust population of microorganisms to have become
established, at least three to six months.
Vampire shrimp do well when kept in relatively neutral
environments with a pH of around 7 and temperatures between
about 75° and 85°F ( 24° and 29°C). In addition to a decent amount
of water flow, they do best with highly oxygenated water. They are
also very peaceful and won’t harass any of your fish. They make great
additions to a community tank, but be careful not to keep them with
species that are going to outcompete them for food.