Fresh water crabs (holthuisana sp.) are normally found in inland rivers, billabongs and dams in northern Australian regions. The different species of fresh water crabs come in varying colour patterns, from tiger stripe to an attractive pale fawn colour with a chocolate brown irregular band crossing from front to the back of the carapace.
Burrow deep
In nature they frequent inland rivers and billabongs that dry up seasonally. They burrow deep into the sand or mud awaiting the next rainy season.
The crabs can construct burrows around 60 cm long. The humid air trapped inside the burrows gives the crabs enough moisture to survive until wet weather returns.
Temperature range
They require a temperature between 18°C and 25°C. Ensure the temp doesn’t fall below the minimum though. A general water hardness of 100-200ppm and a pH of 7.0 is also required. Like any other aquarium pet, water quality is important, they cannot survive for long in soft or acidic water. Due to their temperature requirements, these crabs can be kept with tropical or cold water fish.
Will eat Fish
Fresh water crabs shouldn’t be kept with slow moving fish, or other invertebrates and snails etc. They WILL eat them. Sick or dying fish will quickly be devoured. When mixing species you should ensure you have plenty of hiding places for both the crabs and the fish.
Fresh water crabs make fascinating pets. They are active, hardy and a delight to watch.
Basic Requirements
If you are about to get any fresh water crabs, you need to make sure you have the basic requirements, before you even bring them home! Here is a list of the basic requirements for any fresh water crabs.
- Bowl, Aquarium or Pond
- Filtration (under gravel, corner or power filter)
- Aeration (air pump & air stone)
- Lighting (or natural light)
- Substrate (gravel, sand, pebbles etc.)
- Food (just about any fresh, frozen or dried fish foods)
- Treated/Stabilized Water
Optional Requirements
- Filters
- Aeration
- UV Lighting
- Ornaments
- Plants (live or plastic)
- Test Kits (pH, ammonia etc)
- Aquarium Backing
Breakdown
Suitable For People Aged: 10 & up (they bite!)
Experience Required: None. Care sheet & info
Feeding Care Time Required: 5 minutes a day
Maintenance Time Required: 1/2 Hour a Week
Minimum Space Required: Bowl, Pond or Aquarium
Cost of Upkeep: (approx) $8 Per Week (Power Required)
Life Span: (approx) 5 years
Availability: All Year
INTRODUCTION
Fresh water crabs (holthuisana sp.) are normally found in inland rivers, billabongs and dams in northern Australian regions. The different species of fresh water crabs come in varying colour patterns, from tiger stripe to an attractive pale fawn colour with a chocolate brown irregular band crossing from front to the back of the carapace. In nature they frequent inland rivers and billabongs that dry up seasonally. They burrow deep into the sand or mud awaiting the next rainy season. The crabs can construct burrows around 60 cm long. The humid air trapped inside the burrows gives the crabs enough moisture to survive until wet weather returns.
HOUSING
Fresh water crabs will require an aquarium with surface access. A turtle tank or floating rock is ideal for this. A mangrove root that protrudes high above the water line but away from the sides is ideal. They will periodically come out of the water whenever they feel like it, and it’s believed that they require atmospheric air for their gills to operate properly.
Ensure that the crabs cannot escape. They are apparently great escape artists, and will climb the silicone in the corner of most aquariums. They require a temperature between 18°C and 25°C. Ensure the temp doesn’t fall below the minimum though. A general water hardness of 100-200ppm and a pH of 7.0 1s also required. Like any other aquarium pet, water quality is important, they cannot survive for long in soft or acidic water. Ensure water is treated and free from chlorine, ammonia, nitrite and copper.
FEEDING
They eat anything! Well almost anything. They will eat any type of fish foods, especially sinking fish foods. They will love frozen foods and beef heart etc. They will also eat your fish if they can catch them, so watch out.
SEXING
Sexes are easily distinguished. Males have larger claws, smaller bodies and narrow tails that are folded under the body. Females have smaller claws, larger bodies and wide tails. If claws or legs are lost they will regrow them when they next moult. Adults will grow up to 6cm.
A female freshwater crab lays her eggs at the end of spring. The eggs and the newly hatched juvenile crabs are carried under her body. The eggs hatch in around December each year and the young remain with the mother for several days after hatching. In times of drought, she may carry them for several months, until there 1s enough moisture for them to move on to the next stage of their development. They are unlikely to breed in captivity unless their natural environment and seasonal changes are emulated.
GENERAL
Due to their temperature requirements, these crabs can be kept with tropical or cold water fish. They shouldn’t be kept with slow moving fish, or other invertebrates and snails etc. They WILL eat them. Sick or dying fish will quickly be devoured. When mixing species you should ensure you have plenty of hiding places for both the crabs and the fish.
Fresh water crabs make fascinating pets. They are active, hardy and a delight to watch.
