Increasing water hardness for crawfish? Or changing diet for more calcium?

C

Craw Chief

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Jan 20, 2013
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Hey everyone,

I've just started keeping crawfish again. The water in my area is extremely soft (like 1 dGH/30 ppm GH), but crawfish require hard water (I'd be happy with anything over 7 dGH). I've read quite a bit online about increasing water hardness. So far I've added Epsom salt and an iodine supplement in the prescribed doses I've seen online: Tablespoon Epsom salt per 10 gallons and 1/2 the dosage of Kent Marine Iodine supplement.

Some say the easiest is simply to add crushed coral or limestone. However, the pH in my tank is around 7.5-8, which from what I've read, means those things will not dissolve very well.

Others say to purchase Marine salt and add that to the tank at 1 teaspoon per 10 gallons. If that's the case, what brand of salt should I be looking for? Just go down to Petco and get their store brand of marine salt or what?

There are also some liquid calcium supplements such as Kent Marine Liquid Calcium. I'm assuming I could add that at half the dosage they prescribe (since I'm keeping fresh not salt water).

I'm just looking for some more concrete advice. I like to have specific instructions; i.e., "Go to the store, buy this product, add this much, and the hardness will increase by such-and-such amount."

Essentially, I just want to ensure that the crawfish is getting a sufficient amount of calcium. At present, his diet consists of algae wafers and spinach. Is it possible for the water to be soft and yet provide a sufficient amount of calcium to the crawfish through his diet? Should I modify his diet in any way?

I've seen other members here feed their inverts Ken's Premium Veggie Sticks with Calcium ( http://www.kensfish.com/moreinfo/ken...s-calcium.html ). I'm considering purchasing that due to the good reviews it's received from other invertebrate keepers.

I appreciate any and all advice you can provide! Thank you!
 
Craw Chief said:
I've seen other members here feed their inverts Ken's Premium Veggie Sticks with Calcium ( http://www.kensfish.com/moreinfo/ken...s-calcium.html ). I'm considering purchasing that due to the good reviews it's received from other invertebrate keepers.
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Don't add anything to the tank, especially marine salt. Low doses may be safe but it's a waste of money and I just can see how the cray will enjoy even small amounts of salt in the tank especially after it has molted and is basically bare flesh being exposed.

Ken's veggie sticks with calcium are excellent. My shrimp and marbled crays molt more frequently since I have been buying it.

They also like shrimp pellets (any brand).... and though pricey for the amount, they all love Hikari crab cuisine. I feed it maybe once a week, 2-3 days a week the shrimp pellets and rest of the time veggie pellets with calcium.

Want to the have the happiest cray in the world? As a treat give him a feeder goldfish or guppy (we have a pair of long tongs/tweezers and hold it by the tail). Not to be graphic but the cray will just about instantly rip it half so no suffering..... and he will devour the entire fish like he hasn't eaten in days.

One of our marbled crays are bigger than the rest. My son got a frozen pinkie at Petco one day and there wasn't a spec to be found when it was done.

Stuff like that is just occasional treats though.

I also got some 100% oyster shell calcium vitamin tablets at CVS (sure you can find them at any pharmacy or Walmart). They dissolve pretty quickly. Makes the water a bit cloudy for just an hour or less. I use it in some of my tanks that have ramshorns and mystery snails to help with their shells. One tank has some guppies and for some reason they love eating it too. The pill gets soft fast and the guppies go through them and kick up a white cloud..... it's funny. Then later, their poop comes out almost snow white lol. The crays and shrimp won't really eat them... they can't as they dissolve too fast, but I think it helps with the dissolved calcium in the water.

I'll break one in half and drop that half in a 10 gallon tank maybe once a week or every couple of weeks. I don't think they help tremendously, but it's enough benefit to do it. Sometimes the 100% oyster shell pills are expensive. I found a 500ct bottle at CVS that was on sale PLUS had a buy one get one free.
 
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Calcium chloride ice melter is the cheapest source of calcium supplement. Just be careful, it generates a lot of heat on contact with water, including the moisture in your skin! It's commonly used br reefers as a calcium supplement.
 
I feed snail jello to the crays. It provides calcium and a food source. It clouds the water a bit because the crays shred it so quickly, but it clears up in a day.
 
Thanks for the tips, guys.

OrionGirl, can you link me to the recipe you use for your snail jello? And is that the only food you feed them or do you mix it up with anything else?
 
I feed a variety of algae wafers, bottom feeder pellets, frozen veggies, and the snail jello. I googled for mine, and used one that called for ingredients I had on hand. It used gelatin and water with calcium, fish food, and algae wafers ground up.
 
This is all interesting. What I do for my crawdads is dry an egg shell in the window of the kitchen. When all dry and easily crumpled into small pieces just dump into the tank. They will fight over the pieces. Hope that helps.
 
The cheapest and easiest way to give calcium to crays? Use a cuttlebone that is sold for birds. You can buy them at most any petstore for around $1.00 for 2 and just toss it into the tank. It dissolves slowly and the crays will also graze/eat it.
 
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