Around here, we have the longest living crawfish.
For the past 3 or so weeks, we've fed them, but they survive in the sludge of their own filth. Thay have those little flattened marbles, which they move around. Funny too, they POP up out of the water, or just redecorate....
No, wait, my mistake. Dear Son did change the water and rinse the tank last weekend....
I'm still waiting....