Prepared in a hurry as a circular vortex flow tank for the impending arrival of some riffle shrimp (Australatya striolata).
Rationale:
I wanted a flow tank but didn't have the right sponge filters on hand to whip up a river manifold. Also the 2ft tank I had spare is a bit small to lose much real estate to powerheads and foam filters.
I want to breed the riffle shrimp (either in here if it works in the fresh water).. or I'll be isolating berried females and harvesting the zoea for estuarine larval development. Undergravel seemed the right choice to keep shrimplets out of the pump.
I have dreams of a mini uni-directional flow tank using a river manifold design in a 3ft Bookshelf - 90 x 21 x 24cm tank (like Aww used here).
...or similar but on a bigger scale in a 6x1x1 with some flow loving plants and perhaps some fish ("go large or go home")
...but for now its a case of suck-it-and-see with what I have on hand.
Construction:
* Cheap and nasty bog stock 60cm tank I had given to me. Tank is only 2/3 full to keep the flow up over the rocks.
* Under gravel filter with a THICK gravel bed because I do not plan to clean the gravel often/ever before "upgrading".
* Pump wedged into the under gravel riser is stolen from my wife's old Aquastart 320 tank. The pump is a "straight through" design so uses the little "cap" to direct flow sideways. A traditional powerhead with lateral spout would have been better here but I'm a firm believer of "reduce, reuse, recycle".
* Rocks piled in the middle to "encourage" the flow vortex to form as the triangular cap on the pump isn't all that directional. I might replace it with an elbow later on... but also the lateral spill of the flow against the "main rock" might be a good thing. The shrimp can tell me what they prefer.
* A few plants just because:
Some Rotala rotundifolia "green" and broad leaved chain sword (Helanthium bolivianum "quadricostatus") planted in the clean (so far) gravel. Some Bolbitus heudelotii and Java fern (possibly dwarf) on the rock pile (to block cross flow and encourage a circular vortex flow pattern). There is also a tiny Anubias nana "petite" and the lone Crypt balansae in front of the pump for some schmick lay back down in the flow action.
I'll possibly switch over to native flow loving species in the next upgrade.. this was just a few plant fragments that were cluttering my daughters tank.
Top view below before planting jsut shows the circular riffle - higher in the middle of the tank with lower riffle areas against the front and back glass.
Keeping an eye on the postie for some shrimp this week.
Water and plants are from a previously cycled tank and I'll be augmenting with an already cycled eheim 2213 canister for the startup.
YeeeaaaahhhhhhhhhHHHHH!!!!! 6 years in the making!
Not many larvae given how many eggs the berried females carry. I've been looking into the tank a few times a week for several months now and only ever seeing 0,1, maybe 2 larvae. Tonight I harvested ~30 to attempt rearing in salt water... which is ridiculous when you see the female riffle shrimp carrying around 1000's of eggs. Perhaps my boys are shooting blanks!
09-03-16, 11:53 PM
Hmmm... just noticed its a similar time of year for.....
... 2nd time... going more gently raising the salinity so hoping I can be more successful than last year (esp as I may not get another go until this time next year!).
-no success raising these larvae in marine water...yet
Yesterday I did a 1/3 water change (rainwater + DIY GH booster) and I also noticed the sponge filter was running slowly so I upped the air and therefore the flow in the tank. This seems to have resulted in significantly more larval release. Perhaps the shrimp respond to rain storm events as a trigger for larval release.
I siphoned them out into a 50µm sieve and then into a moccona coffee jar with some of the tank water.
For DAS It takes about 1 month for them to metamorphose into post-larval juveniles in salt water. > here
For Riffle shrimp its an unknown quantity - lots of people report breeding big egged Riffles without salt in the tank with the parents. I've not been successful over a couple of years. The science literature says they breed in estuarine conditions. My shrimp may have come from locations closer to salt water than some other peoples shrimp (mine were bought from livefish.com.au). So I'm trying some salt at a number of concentrations by splitting them into a couple of coffee jars with different salinity and hope one is successful.
Cursed again... but the longest survival by a reasonable qualitative magin was in the 20ppt salt compared to 10ppt and 25ppt ... and I have more shrimp berried so will have another crack.... on the upside I just got a few hundred more DAS through and some typus so its not all bad - I know a few people now that have riffles that will breed in the tank in fresh water... but not mine.
