Vacation Feeders Have Calcium

[jlOisAhoTti]

Are they a good idea to feed to crayfish?

 

[Colin_T]

Not unless you are going on holidays for a long time.
Crayfish do best on a varied diet. They will eat most things including fish and plants. Most fish foods are fine but pieces of fruit & vegetables like pumpkin and zucchini are often taken. Live plants will usually be eaten.
They generally get most of the calcium they need for their shells from the surrounding water. If you have hard water (lots of minerals in it) then you shouldn't need ot worry. If you have soft water then add some rift lake conditioner or calcium supplements from the LFS.

 

[TylerFerretLord]

You can also add some coral gravel in a filter bag to the filter, or shells or calcium based rock to the display. It's a lot easier than dosing with every water change, in my opinion.