That's why I haven't made one yet. I'd like to make one that contains a correctly proven amount of every nutrient and will, for a fact, stay alive for a long long time.
Ironically, we're doing it to ourselves at the global scale, to ourselves and tons of other organisms. It's only when the scale is so small that we can hold it in our hands, that we start to empathize.
I find them more cruel, as you knowingly doom your pet world to die a few years later.