Crayfish help

Question
Hello. I was wondering if you can help with this one. I have just caught some
crayfishes(3) at a river and decided to keep them as pets. I have kept them in a
ice chest with water from the river until I was able to find a tank that will
suit. Once i got a tank, I filled it up with some purified drinking and put them
in. The next morning, I found two of the smaller ones dead. Now I only have one
large one left and he seems to be doing fine. What went wrong? Is their a certain
type of water that they could only tolerate? Thank you.

Answer
Hey Joel,

What you're experiancing is transplant shock. Crawfish typically live in fast flowing river settings with rocks and wood to hide in. Because you scared the daylights out of them catching them, moving them around and throwing them into a lake-like bucket, you've stressed them out to no end. Once settled in their bucket and calming down, you threw them into a new bucket with completely different water quality. The difference in quality at this point would feel like dropping mild acids on your skin (not advisable!!) The crawfish had been severely stressed out, and now have water with different pH (rivers tend to be higher then 7.0, which bottled water is). The salt level is surely different (rivers tend to be around 1.007, bottled water is 0.000-0.005), and, they probably have not eaten in a few days and were out hunting. Now in your tank, to help keep this one alive, do a water test on the river for everything. Do the same test on your tank. Adust the pH, hardness, salt, iron, and everything else to match the river. Get some good crawfish foods (like brine, pellet, or slow moving live fish.)

Once all that is settled, build your tank so the filter is on one side, pushing water to the far end length wise, run a hosing from the filter intake to the far side of the tank, shove a sponge in the end of the tubing, and leave it resting just above the gravel. the tube running under the gravel will be well hidden, and the tip above gravel will create a flowing, river like movement above the water. This movement is key to making the crawfish feel more at home. Gather some river rock together and make a decorative setup along the back wall that has little caves and hiding places, but wide open room in the front. This gives your crawfish hiding grounds, hunting grounds, and lets you see him no matter where he goes! Even in a small 10 gallon tank, this is easier to set up then most people think.

With a good set up, good water, and good food, your crawfish should be a happy pet in it's new home. However, next time, consider buying them at the pet store! domestic crawfish are usually only 4-5$ US and thats in the dry south-west coast where we dont have too many wild ones!

Best wishes, and good luck!