An Unsafe and Inhumane Practice

The question of whether one should intentionally remove the claws or de-thumb the claws of their crayfish is constant reoccurring question in the aquatic community. However, it is neither a safe or humane practice and should not be attempted for the following reasons:


1.) Contrary to popular belief, crayfish actually have a fairly extensive and complex nervous system. And as such, this process is likely to not be entirely painless as once thought. The extent of the pain they feel is not yet determined (the debate between whether noxious stimuli results in pain or not, and if so to what extent, etc), but as time goes on more and more scientific studies are showing that invertebrates (especially decapods) may closely experience similar pain to that of vertebrates.

Additionally, the belief that because crayfish possess the ability to regenerate their lost limbs is an indicator that they cannot feel pain is also incorrect. Crayfish do not go around throwing their limbs off because they feel like it. It's an evolutionary adaptation that's beneficial to their survival, that is all.


2.) The process of removing the claw as a whole or merely de-thumbing leaves open wounds on the crayfish. These open wounds can easily become infected with any number of bacteria, micro organisms, fungi, etc (even in the cleanest of tanks) that can cause severe damage or death to your crayfish.


3.) Additionally, contrary to popular belief, the removal of the claws or the de-thumbing of the claws will not stop your crayfish from catching tankmates or eating plants. Crayfish do not need their claws to eat your plants, and I personally, have had any number of crayfish with lost limbs still manage to catch fish, shrimp and snails (the rate at which they were caught and the number of total caught was decreased, but it still occurred).


4.) And from a personal stand point, the most important reason not to engage in these acts is because you should not be modifying your pet to suit your needs. If you want to have a pet it is your responsibility to set-up a proper environment and take care of it in a manner that suits it, not you. If you don't want to take the time to pick out animals that can co-exist peacefully or set-up separate enclosures for those that can't, don't get the animal(s).


Sources:
Museum of Comparative Zoology, The International Scientific Series - Volume XXVIII
Bluecrayfish.com
Crayfishmates.com
Brusca & Brusca 2003
Sentience and Pain in Invertebrates (2005)