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    • Linden
      By Linden
      Hello. I've written the following based on my own time scouring the internet and then personal experiences with my mud crab Gaston.      Mud crab aquarium care.    Tank setup: Minumim 4ft aquarium. A 4x2 ft much better.  Like with turtles, larger footprint is important. Not so much how tall the tank is. Seriously big crabs. Be open to having a 6ft aquarium if you plan on risking tank mates (other than glass shrimp, snails and tiny fish). Unless your in Western Australia, you'll get Scylla serrata aka Green mud crab (not named green for being green. Can be brown and blue also). They can grow up to 30cms and 2.5kgs with 20cm claws.   Have a cycled aquarium with brackish water about 1.006-1.010 SG. Heated 19-25°c. PH around 7 or higher. Harder water is important. Crushed coral can help balance out soft tap water and the use of driftwood. Breaking up some cuttlefish bone in the water column is important. Calcium for shell development. They are from estuaries. So have a great tolerance for temperature and salinity fluctuations.   Decent filtration is a must as they are exceptionally messy eaters. I recommend a sump. The crabs are very strong and can snap heaters, damage power cables and move tubing. So a sump for the hygrometer and heater helps, with the benefit of the overflows and returns being secure. Also clamps to hold parts in place. Pvc tubing can be used to protect power cables and keep equipment protected.   The lid needs to be very secure. With only small gaps and also weighted down. The crabs are strong and can easily lift glass. Some additional glass pieces on the lid to keep it down is recommended.     The crabs will want to get their mouths above the water line periodically. So don't fully fill the aquarium. About 20cm deep. Deeper depending on if you have driftwood or rock climbing areas so it can still reach above water line. Note: ensure all rocks and driftwood are very securely and purposefully positioned. Remember they are very strong and can move unsecured rocks and driftwood. Poorly placed rocks could be moved and break the tank. Using larger rocks and wood is safer than easier to move small pieces.   Sand as a substrate is best. 6cm or so deep. Mixed with some crushed coral and aesthetic gravel. They sift through sand for scraps plus it will help fill cracks between rocks n such to secure them even more.   They will eat plants. So not a great aesthetic addition.     Don't put strong lighting on the tank. The crabs like to hide. Plus they'll grow algae over their carapace under too strong and or long exposure. Glass shrimp will help keep this down.    Aquiring:  Can be bought from a fish market. Sold as live food. About $50 per kilo. A standard mud crab will be about 0.8-1.4kgs. Google how to pic a healthy mudcrab. You want to select the healthiest male you can get (not the biggest). Note. They'll all be male.  Transport in Styrofoam box or esky with a little ice. They'll wrap it in newspaper.   When home. Unpack it (keep the claw string on) then move it into a large container or tank with no water for about an hour as they 'defrost'. Remove the claw holding string as you move into their aquarium. Have a friend around to help with lid for safety reasons.    Feeding:  They are scavengers and eat a wide variety of foods. They will make a big mess when they do, so some glass shrimp, Malaysian trumpet snails and a few tiny fish are beneficial for cleaning up the shower of food particles.   My favourite foods to feed are small whole cooked tiger prawns and marinara mix from the deli. Some white fish cut into pieces then frozen. Repashy with added calcium (powdered egg shells or cuttlefish bones). Make big skeets in flat zip lock bags and freeze. Snap off a piece for feeding.     Can also feed worms, clams, scollops, crab pieces, garden snails, plant matter (like excess Elodea from another tank).  A varied diet is important. But most of all is getting plenty of calcium in their diet. The repashy +calcium or a similar diy mix with agar agar, calcium, seafood and added vegetables is gold.     It might not take to eating well initially. I recommend using long planting tweezers. Carefully. Don't want them to grab the tweezers.   You can train them onto eating by attaching a piece of meat or prawn to some cotton string. Jerk it around infront of him until he goes for it. Might take a few tries. Don't leave large pieces of uneaten food in the tank to spoil. Be very careful putting hands into the tank. They can go from slow to very fast moving in an instant.  Here's my Gaston. 

    • wayne6442
      By wayne6442
      Australian Freshwater Crab
       
       
      Freshwater crabs can be found in the tropics and subtropics in most parts of the world. Out of a total of 6,700 species , there are more than 1,300 described species of freshwater crabs,and many more currently unknown to science.
      The IUCN (International Union for Conservation of Nature ) Red List has assessed all described species as “ data deficient”, as data on their ecology, reproductive biology and habitat requirements is lacking.
       
                                                                                       (Austrothelphusa Transversa)
                                                         
         
      The majority of species studied to date tend to occur in small geographic areas, have poor dispersal abilities and low fecundity (the ability to produce an abundance of offspring) thus making them highly susceptible to land use alterations, river regulation changes and climate change.
      Scientists in Australia are investigating the biology and ecology of our remarkable freshwater species in the tropical regions of northern Australia and the Torres Straits. Very little is known about many of the far northern species, however science has discovered that they have an amazing lifecycle, these crabs will dig tunnels in the creek banks at the end of the wet season and spend the hot and dry times in a prolonged state of torpor/dormancy, emerging again at the onset of the next seasons rains presumably to feed and reproduce. Females of the species A. Transversa have been documented carrying their young
      under their abdomen underground during the dry season and when the wet season arrives they will leave their mother growing up quickly before the next dry season.
       
                                                                                     
                                                                                                               A.Transversa
      The most common species of freshwater crab found in the aquarium market in Australia are the Holthuisana sp. (Austrothelphusa) There are several sub species in this order:
      A. Agassizi
      A. Angustifrons
      A. Receki
      A. Tigrina
      A. Transversa
      A. Valeatula
      A. Wasselli
      With the most common on the market being A. Transversa and A. Agassizi :
       
       
       
       
                                                                                         
                                                                                       
       
                                                                                     A. Agassizi (Freshwater Brown Back Crab)
       
      CARE:
      The two species A.Agassizi and A.Transversa are by nature amphibious and should be provided with an “Island” where they can leave the water at will . It seems they require atmospheric air for their gills to operate properly.
      In nature these crabs frequent inland rivers and billabongs in northern Australia that dry up in the winter.
       
      Water Quality:
      Temperature: 18 deg C. to 25 deg C.
      pH: 6.5 ------7.5
      General Hardness Soft /Moderate
      The freshwater crab can not survive for long in very acid water. Make sure their wateris free from ammonia,nitrate and copper.
      Feeding:
      A true scavenger, they will eat most types of sinking fish food, blood worms, fresh vegetables
      and sometimes aquarium plants.
      Colour and Varieties:
      The A. Agassizi ( Brown Back Crab) can come in a variety of colour patterns e.g with an attractive pale fawn colour, with a chocolate brown irregular band crossing from front to back of the carpace or even a tiger stripe pattern. While the Colours of A. Transversa is mainly a shade of brown from yellowish to deep redish.
                                                       
                                                       
       
      Housing:
      Both species are great escape artists and can easily climb the silicone in the corners of most tanks. I have had them climb up air hoses and the water pick ups for the filters.
      They are fairly peaceful and can be trained to come to your fingers for food. If kept in a community tank ensure that there are no slow fish as the crabs are not adversed to a little fresh fish in the m
                                                                                                   
       
       
                                                                         
       
      Disclaimer:                                                                         A. Transversa
      The information provided here is of a general nature only.
      Citation: The IUCN red list
      Dr Nathan Waltham: Ecology of Freshwater Crabs in Tropical northern Australia
    • wayne6442
      By wayne6442
      Australian Freshwater Crab
       
       
      Freshwater crabs can be found in the tropics and subtropics in most parts of the world. Out of a total of 6,700 species , there are more than 1,300 described species of freshwater crabs,and many more currently unknown to science.
      The IUCN (International Union for Conservation of Nature ) Red List has assessed all described species as “ data deficient”, as data on their ecology, reproductive biology and habitat requirements is lacking.
       
                                                                                       (Austrothelphusa Transversa)
                                                         
         
      The majority of species studied to date tend to occur in small geographic areas, have poor dispersal abilities and low fecundity (the ability to produce an abundance of offspring) thus making them highly susceptible to land use alterations, river regulation changes and climate change.
      Scientists in Australia are investigating the biology and ecology of our remarkable freshwater species in the tropical regions of northern Australia and the Torres Straits. Very little is known about many of the far northern species, however science has discovered that they have an amazing lifecycle, these crabs will dig tunnels in the creek banks at the end of the wet season and spend the hot and dry times in a prolonged state of torpor/dormancy, emerging again at the onset of the next seasons rains presumably to feed and reproduce. Females of the species A. Transversa have been documented carrying their young
      under their abdomen underground during the dry season and when the wet season arrives they will leave their mother growing up quickly before the next dry season.
       
                                                                                     
                                                                                                               A.Transversa
      The most common species of freshwater crab found in the aquarium market in Australia are the Holthuisana sp. (Austrothelphusa) There are several sub species in this order:
      A. Agassizi
      A. Angustifrons
      A. Receki
      A. Tigrina
      A. Transversa
      A. Valeatula
      A. Wasselli
      With the most common on the market being A. Transversa and A. Agassizi :
       
       
       
       
                                                                                         
                                                                                       
       
                                                                                     A. Agassizi (Freshwater Brown Back Crab)
       
      CARE:
      The two species A.Agassizi and A.Transversa are by nature amphibious and should be provided with an “Island” where they can leave the water at will . It seems they require atmospheric air for their gills to operate properly.
      In nature these crabs frequent inland rivers and billabongs in northern Australia that dry up in the winter.
       
      Water Quality:
      Temperature: 18 deg C. to 25 deg C.
      pH: 6.5 ------7.5
      General Hardness Soft /Moderate
      The freshwater crab can not survive for long in very acid water. Make sure their wateris free from ammonia,nitrate and copper.
      Feeding:
      A true scavenger, they will eat most types of sinking fish food, blood worms, fresh vegetables
      and sometimes aquarium plants.
      Colour and Varieties:
      The A. Agassizi ( Brown Back Crab) can come in a variety of colour patterns e.g with an attractive pale fawn colour, with a chocolate brown irregular band crossing from front to back of the carpace or even a tiger stripe pattern. While the Colours of A. Transversa is mainly a shade of brown from yellowish to deep redish.
                                                       
                                                       
       
      Housing:
      Both species are great escape artists and can easily climb the silicone in the corners of most tanks. I have had them climb up air hoses and the water pick ups for the filters.
      They are fairly peaceful and can be trained to come to your fingers for food. If kept in a community tank ensure that there are no slow fish as the crabs are not adversed to a little fresh fish in the m
                                                                                                   
       
       
                                                                         
       
      Disclaimer:                                                                         A. Transversa
      The information provided here is of a general nature only.
      Citation: The IUCN red list
      Dr Nathan Waltham: Ecology of Freshwater Crabs in Tropical northern Australia

      View full article


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    • kms
      Mine is a DIY Chiller, as you know a peltier has a hot side and cold side, for the cold side to stay cold, the hot side must be kept cold and with a heatsink and fan to cool it down. My DIY chiller has two sides and two water block. blue aluminum block with tube leading to the outlet of the canister filter and back to the tank to chill the tank water. copper block is to cool the hot side of the peltier, with copper block to the radiator/fan and a water pump looping. The problem is the tube from the water pump came off, apparently the plastic from the pump started to melt and the tube came off and the looping side had no water, so the copper water block stayed hot all the time with heat transferred to the cold side of the peltier also heating the water. since the copper takes time to cool down, most of the heat and the room hot temp had already heat the tank water to about 45 C.
    • sdlTBfanUK
      Try testing it again and see what you get or to confirm that the previous were right, especially the higher Ph reading is all I can recommend! If there is some explanation for the difference hopefully someone will reply and let you know, but I expect there won't actually be a difference if you do it again? Simon
    • jayc
      No that's not normal. But I don't know which tube in your loop had come off. Can you show us?   Yes that would have helped a bit, and at least give KMS more time to have found the issue by turning off the chiller. As I understand, kms has a peltier style chiller, and a tube of the pump had come off, which meant that hot water from the hot side of the peltier flowed back into the tank. So if the chiller was on the same temp controller, it would have turned off the chiller at around 26degC. The tank might have got warmer in his room, but it would have been at a much slower rate, and certainly would not have reached 45degC.
    • kvinnyy
      I'm using the API master test kit with the dropper bottles. I was just very confused at how much more akaline the water was coming out of the filter compared to the water out in the open. I can't imagine how this fluctuating change in pH is going to be beneficial for my crs.
    • sdlTBfanUK
      What type of test are you doing strip or drip? I use drip tests and always ignore the first attempt as no matter how well I clean and keep the test set it is often way out of line. Las time first test was Ph8, second test Ph6. Sometimes first attempt looks ok so I have no idea what is going on????? If you just tried once it may be worth testing again? Simon
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