Blackwater - everything you mentioned regarding the benefits you give your fish is all that a companion of any kind would want - whether it be a dog, cat, reptile or other. There are however levels of cruelty that occur when it comes to all animals when in the wrong hands. You know if the animals you keep are unhealthy or unhappy imo.
with this, if one is a serious fish keeper then the fish will receive 100% better care then they would receive in the wild...