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FAQs on Freshwater (and Terrestrial) Crustaceans, Systems 

Related Articles: Freshwater CrustaceansInvertebrates for Freshwater Aquariums by Neale Monks, Forget Crawfish Pie, Let's Make a Crawfish Tank! By Gage Harford

Related FAQs:  FW Crustaceans 1FW Crustaceans 2, FW Crustaceans 3, FW Crustaceans 4, & & FAQs on: FW Crustacean Identification, FW Crustacean Behavior, FW Crustacean Compatibility, FW Crustacean Selection, FW Crustacean Feeding, FW Crustacean Disease, FW Crustacean Reproduction & Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction, Freshwater Shrimp, FW Crabs, Terrestrial Hermit Crabs, & Marine Hermit ID, Hermit Behavior, Hermit Compatibility, Hermit Selection, Hermit Systems, Hermit Feeding, Hermit Reproduction, Hermit Disease/Health, & Crayfish FAQs, Crayfish 2, Crayfish ID, Crayfish Behavior, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Disease, Crayfish Reproduction,


Calcium in Crab & Shrimp Tanks     6/2/16
I keep a few crustaceans (Panther crabs, Rainbows crabs, Geosesarma crabs, Crayfish and Cherry Shrimp). I know that calcium is important for the proper development of their shells. I have looked all over the net and can't find any definitive information on how much calcium and how often it's needed, so I'm hoping you can help.
I bought some small calcium tablets (1" long by .5" wide), but I haven't put them in the tanks yet. I need to know how often I should be giving my crustaceans calcium and how much. So far they've been doing good but I want to make sure they have the best care possible.
Any help is much appreciated. Thank you.
Kind Regards,
<As with humans, it's the "bio-available" Ca that is important; and for freshwater organisms this takes the form of both dissolved and macro-sources. Unless you have a Calcium concentration test assay, I'd rely on "hardness" as a measure here; and aim for "medium hardness" (measured in various ways: https://en.wikipedia.org/wiki/Hard_water
AND I would use the small calcium tablets you mention (or softer sea shells, cuttle bone) as an exogenous source these animals can/may pick on.
Bob Fenner>

New Terrariums from Penn-Plax  8/25/09
Hey Bob and Crew,
Just thought I'd let all your loyal readers know about 3 new lines of terrariums that Penn-Plax is introducing under the Reptology name. Some very exciting products for all your readers that are also into reptiles
and amphibians, please check out the video -
<Nice units.... lots of good features. Neat video>
Thank you as always.
Paul Demas
Project Manager
Penn Plax, Inc
<Welcome. Bob Fenner>

Triops Water Problem -- 10/13/08
Thanks for answering a previous set of questions about raising Triops.
<Most welcome.>
Unfortunately I'm still having problems despite trying to do everything right. Here's what I have now:
Triops australiensis eggs hatched in 3 liter tank in distilled water with small pinch of bicarbonate of soda per Billabong Bugs instructions.
11 hatchlings, now 9 days old. Feeding TetraMin flakes and carrot.
Hatching tank is floating in larger 20 liter aquarium with heater and subgravel filter. Temperature is 25C for both. Hatching tank has a simple air line producing a small bubble every few seconds. Sand substrate came with Billabong kit.
All seems well there, so far. pH 7.5, GH 3, KH 1, no detectable ammonia yet. Some cloudiness. Rapid growth, they are now 6-8 mm long and growing fast. I have been doing partial water changes < 10% daily with the larger tank water. They will need to move soon to larger quarters.
<Sounds like it!>
Larger aquarium is fully cycled using fishless method. Ammonia tests at zero ppm. Nitrite tests at zero ppm. GH 6. KH 3. pH 7.5. If I add 5 drops of household ammonia, the ammonia and nitrite will drop to zero again within a day. Added one half a drop of Kent iodine a week ago. 50% water was changed after cycling to reduce nitrates -- plants have been growing for a month.
<All sounds fine.>
The aquarium is planted with Cryptocorynes which are doing well -- divided 2 original pots into 13 small to medium plants. Aquarium is in north facing window. No algae growing, probably because plants are using up excess nitrates. Plants have produced new leaves. Some pet store Cyclops and tiny snails came in accidentally with the plants. I kill the snails by crushing when seen. I figure the Cyclops will end up food when the Triops are added to the large tank.
<Likely yes, the Triops will eat any small animals they can catch.>
The problem: I added 3 Triops to the large tank today and all gradually became distressed. Two immediately started continual looping behavior.
One fed well for a day, then seemed to have problems --possibly a molting problem. One looper died overnight. The molter is still alive but struggling.
<May be stressed by the water chemistry change. Personally, would avoid adding anything (e.g., Iodine) unless expressly told to do so by the manufacturer. These animals live naturally in low mineral content waters and are presumably adapted to such. In any case, humbly suggest hatching them in one tank and then rearing them in another is not the way forward. Would rather hatch in the big tank with minimal water level, and then gradually add more distilled water (as if it were rainfall) a cm or so every couple of days.>
The water in the two tanks was exactly the same temperature when transferred. No net was used, they were simply gently poured in. The hatching tank had been gradually exchanging water with the main tank through water changes. The specs don't seem that different, and they should be acclimated pretty well.
<You'd have thought... but apparently not.>
I just don't understand what is going on. Possibly a dissolved metals problem? Wouldn't that affect the other thriving invertebrates (snails and Cyclops). Or is it a hardness problem? Should there be calcium in the water. If so, then why are the Triops in the softer (nearly distilled) water doing well so far?
<Triops live in very specific habitats, and it's essential you stick precisely to the "Recipe" the manufacturer of the Triops eggs provided. As nice as it might be to see them swimming about a planted tank, that may not be viable. You could try and hatch some eggs in a soft water planted aquarium, but hatching them in distilled water and then moving the babies to a soft water aquarium might not work. I'm speculating here of course, and I don't believe any of us here are Triops experts. I kept the European Triops cancriformis for a while and only managed to rear a single specimen to adulthood. Would heartily suggest joining one of the many Triops forums or Yahoo Groups where you'd be able to talk to actual experts.>
My tap water tests pH 6.5, GH 6, KH 3, no ammonia, no nitrite, no chlorine (it is natural artesian spring water). Could be some manganese and iron as there are some small rust stains on bathroom bowl porcelain.
I have to figure this out, because they can't stay in the 3 liter tank much longer -- the growth rate is too rapid, it's just too small. Any suggestions? Change 50% of the main tank water with distilled?
<Hatch, rear the Triops in a single container with consistent water quality. Add a sponge filter only once mature enough not to be sucked up. That, I'm afraid, seems to be the recipe that works most reliably.>
Thanks for your help!
<Cheers, Neale.>

Shrimps and Iodine Hello again, seems like I'm pestering you folks a lot with invertebrates questions lately.  I was looking through the Freshwater Snail FAQ again, and noticed a note by Sabrina <Me!> that freshwater shrimp tanks can/should be dosed with iodine <I first got this notion from another person that had asked about it, and I got the dosing rates from the fella at http://www.franksaquarium.com/ , in case you (or others) wished to know.> (she recommended Kent reef iodine - I found a bottle of Kent's marine iodine while browsing an LFS this weekend and picked it up) at a rate of one drop per ten gallons every week, and that it may help snails as well. Getting to my questions, does the iodine break down over time in the tank, or get absorbed by the charcoal in the filter, or what? <It'll get used up by the shrimp, and will break down in time> Also, is there a way to measure the amount in freshwater, and would you be able to suggest a recommended level? <I think it highly impractical to test for it....  Iodine tests are very awkward and time consuming, and I'm not even positive they'll work with freshwater.  One drop per ten gallons weekly is a very, very small amount, but really does improve overall health of the shrimps.> I've been told there are iodine test kits for reef tanks, but the individual who told me that wasn't sure if they would work in freshwater. <Yeah, I rather doubt that it would.> I change approximately 10% of the water in my tanks weekly, and 25% once a month, would that be enough to remove any excess to prevent buildup?   <I think you'll be absolutely fine with that.> Additionally, can the iodine harm fish or other life forms in the tanks? Other than ghost shrimp and mystery snails, the other tank inhabitants are black phantom tetras and Otocinclus (golden Otos, I believe) in one tank, and African dwarf frogs in the other.   <I don't know much at all about the frogs - but everything else should be great.  I've used this in a heavily planted tank with some pretty sensitive fish, with absolutely no effect on the fish (or plants) whatsoever.  Wishing you well,  -Sabrina.> Thanks again for any help you can provide,  Chris

Crayfish Hi Bob Fenner I have a 2.5gallon tank with a crayfish and a 29gallon hard alkaline cichlid tank with a divider. I want to move the crayfish to the empty portion of the 29gallon tank and was wondering how to go about acclimating him from his neutral water. <I would "drip acclimate" the crayfish/crawdad to the new water by placing it in a lower position, dropping half the water out, and use a length of airline tubing (with an adjustable knot) to drip (about one drop a second) the cichlid water into its smaller system... Most species (yours... likely an astacid... maybe Procambarus clarkii?) will make this transition easily... after this abrupt mixing, just place the animal by scooping it into a bag or plastic container underwater and put in the larger system> Ps. I appreciate your past help, and the speed at which you have replied. <You proverbially "ain't seen nothing yet". Bob Fenner>

Crayfish I was wondering wither I could successfully keep a crayfish in a 2.5gallon tank with a sponge filter. <it would be a little cramped, but it would likely work too. They are incredibly hardy creatures.> 

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