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FAQs on Freshwater (and Terrestrial) Crustaceans, Foods/Feeding/Nutrition 

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 Systems, 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,

Red Claw Crab not Eating 12/29/19
Hello! Hardly anyone knows anything about red claw crabs, as I cannot find any answers as to why my red claw crab has stopped eating!
<Let's see if we can help.>
He is kept in brackish water conditions, has filtered water, and water that is always about 74 degrees Fahrenheit.
<Right. Let's review first. By "brackish", how salty are we talking about? The first thing you do when brackish water animals misbehave is change the salinity. Many if not most come from places where the salinity varies, so just making a change can have a positive effect. But the bigger issue is that you need to be using a substantial amount of salt, not the teaspoon per gallon amounts often mentioned. I'd suggest one teaspoon per litre (i.e., a salt concentration of about 6 gram/litre) to produce about one-sixth normal seawater salinity. If that didn't do the trick, feel free to double that amount, which would get you around one-third normal seawater salinity. Either of these would be much closer to real world situations for Perisesarma bidens. Next up, review air temperature. 23 C/74 F is very much towards the low end for a tropical animal, and I'd crank the water heater up to 25 C/ 77 F. In cold conditions tropical animals will slowly lose vigour, and loss of appetite is an extremely common symptom of that. Death invariably follows soon after, though it may take weeks to happen.>
He is able to climb to get air or be in water when he wants. I have sand substrate. When I first got him, he would eat his food fine, but now, he won’t eat at all. I noticed he wouldn’t eat, so I ended up putting his food right in front of him, and he still won’t eat that food.
<Loss of appetite in crabs is almost always a symptom of environmental problems. Review as stated above.>
I don’t think he’s molting, because he’s been acting this way for about 2 weeks and I was told molting should only take about a day.
<Correct, and moulting crabs tend to hide away. They do need a source of iodine to moult successfully, for which purpose either offer regular portions iodine-rich foods (Sushi Nori is ideal) or else specific iodine-enriched crustacean foods sold for use in marine aquaria.>
Also, I don’t think it’s a calcium problem, as I give him special vitamins that help provide him calcium every 3 weeks. I’m really worried about him, and I have no idea why he is not eating.
<Hope this helps. Cheers, Neale.>
Re: Red Claw Crab not Eating       1/1/2020

Thank you very much for this help! Right after I added more salt, he molted the next day.
<Great!>
Does he absolutely need to eat his exoskeleton? If so, he is not eating it.
<No, he doesn't need to eat it, but most crabs do, simply to recycle the calcium. If he doesn't, that's fine, but do add some suitable replacement, like a small shell-on prawn that he can pick apart and consume. Failing that, just dusting whatever he likes to eat (fish meat, banana, etc.) with crushed cuttlebone or even fragments of edible snail shells (escargot) will have the same usefulness. Some crab foods are calcium-enriched and may be good enough on their own, but personally, I'd make a point of offering
extra calcium immediately after moulting. Cheers, Neale.>
Re: Red Claw Crab not Eating   1/11/20

I’d like to thank you for helping me with my red claw crab. Unfortunately, he has passed away even after adding a proper amount of salt and turning up the temperature, as he just did not eat at all.
<I'm sorry to hear that.>
I don’t know the reason for his refusal to eat, but after taking your advice, he seemed to have more energy and would actually approach the food (but still didn’t eat it). Maybe he was sick?
<Indeed, or perhaps, he'd been away from salty water for too long. These are tricky animals to keep well -- they need brackish water, high humidity (cold or dry air quickly kills them), and food that contains all the nutrients including iodine and calcium. So while inexpensive in themselves, and not demanding in terms of space, they are tricky.>
I don’t know, but I’m glad I found your website and got some help. You are very knowledgeable about these creatures, and people who are having trouble with their pet crabs are fortunate enough to be able to contact you for help. Again, thank you very much.
<You are most welcome, and thanks for these kind words. Good luck with your next pet! Cheers, Neale.>

Calcium in Crab & Shrimp Tanks     6/2/16
Hello,
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,
Suzanne
<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>

Ghost Shrimp Hi! Can you tell me what ghost shrimp eat? <Just about anything you offer them meat based.> <You are welcome. -Steven Pro>

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