I have a 30g. freshwater tank that currently holds a crayfish that is around 3 years old. I have it sitting on my bar in my kitchen. It's a pretty bare tank with only one occupant in it. At one time it held several large koi's but in my stupidity from being new to the whole fish tank thing I made the mistake of including the crayfish in the community. In a few months time the crayfish killed all the koi's and ate them :duh: . So since its just sitting there, I decided that I want to move it into the living room and get some new fish for it. One problem... The crayfish. I can't include it with anything since it will eat them. I was thinking about catching it and taking it too a local lake and releasing it. My question is this a good idea? After having been in a tank for 3 years will it survive in the wild or would it be a better idea to just put it down? The other option I have is a 10g. hexagon tank that I could move it too. But once again is this a good idea? Once I figure out what too do with the crayfish and get the tank moved I want to remove the gravel and replace it with some brighter color gravel. The tank needs some serious cleaning. I know I can use the algae pads and what not, but are there any non toxic cleaners I can use to facilitate the process? So any ideas about how too handle the crayfish situation and cleaning suggestions would be helpful.