system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why don't sharks last long in captivity?
gpt
Sharks aren't the most robust fish species, and size, diet and activity effect the health of all fish species. Sand tiger sharks and species of cat shark are often kept in aquariums because of their size. Another contributing factor is the build up of waste and size stunting in a tank rather than an entire ocean.