Hey guys, just found an add for this website showcasing a cool-lookin native algae eating shrimp.
Anyone heard of these before or own any? My interest was peaked by the claim that they eat hair-type algae, as I have some on my crypts and lace fern that I cannot remove. And for a price of $4 ea, and super easy parameters, they sound pretty doable!
Tell me more oh great SKFians! 😁
(or feel free to point me towards an already existing page)
post-note: have you/do you keep these grubs? Seems like your sort of thing.
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.
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.
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.
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:
With the most common on the market being A. Transversa and A. Agassizi :
A. Agassizi (Freshwater Brown Back Crab)
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.
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.
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.
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