They seem to be about equal in satiation to the purchased packs, but the type of fish doesn't matter as far as I've ever been able to tell. However I think you can also use the fish that can't be eaten (goldfish, guppies, etc). (Tip: Fishing is a poor way to feed a squeamish vampire. Speaking from experience.)
For gardening, if I'm starting from nothing, I usually try to find blackberries, strawberries, and snapdragons and work up from there; they seem to have the largest payout. While developing the first few levels I go for quantity over value but cut back as the worth of individual plants increases, or the garden can become unmanageable quickly. Keep evolving every time you can. If you look up the grafting recipes, you'll be able to get more valuable hybrid plants by combining two common ones, such as strawberries+snapdragons=dragonfruit. Dragonfruit sells very well. Flower arranging also gets lucrative toward the higher levels, especially if you're growing your own materials.
