Question: What do you think of feeding fish (and ‘standard’ canned pet food) to cats and dogs, while being vegetarian personally, with chanting of the Rebirth Mantra (往生咒) for the fish, in hope that they reach Amitābha Buddha’s (阿弥陀佛) Pure Land (净土)? Is this alright?
Answer: You have to decide who to have compassion for – the fishes, cats and/or dogs. If there is continual purchasing of fish, even if pre-killed, you will still play a part in the cycle of supply and demand cycle for further killing. As part of the Bodhisattva path of expanding compassion for more and more beings, why not practise compassion for all involved, by choosing vegan food (i.e. that without any meat and other animal by-products, such as milk, eggs, and honey… as they all come from animal exploitation ending in killing) for yourself and the animals involved?
As taught by the Buddha in the ‘Thirty-Second (Secondary) Bodhisattva Precept Against Harm Of Sentient Beings’ (第三十二损害众生戒) in the Brahmā Net Sūtra’s Bodhisattva Precepts’ Text《梵网经菩萨戒本》, ‘If as the Buddha’s [Bodhisattva] disciples, they should not… nurture cats, raccoons, pigs and dogs. If there are those intentionally raising them, they commit a light defiled transgression.’ (若佛子，不得… 长养猫、狸、猪、狗。若故养者，犯轻垢罪。)
What the Buddha meant is not to forgo compassion for animals, but that they should not be purposely caught, imprisoned and reared for selfish reasons, (what more with feeding of other animals to them). As the exception, taking care of sick and injured animals before freeing them to their natural environments is alright. Of course, if there are pets already domesticated, who are not used to the wild, there should be continual care of them. As an example of a vegan food alternative for cats and dogs, be they domesticated or strays, there is https://www.kohepets.com.sg/products/wysong-vegan-formula-dry-cat-dog-food More kinds can be found online and offline.
On whether simply chanting will definitely help deceased animals reach Pure Land, do see https://thedailyenlightenment.com/2011/07/quickly-kill-to-deliver-me-please (In short, if it works so easily, we ‘might as well’ kill each other while chanting for each other immediately. Of course, as it does not work so easily, we should not do this.) These considerations on feeding stray animals might be of interest too: https://thedailyenlightenment.com/2018/01/are-stray-feeders-bodhisattvas
Thank you for your kindness to all sentient beings.