I think it's great to rescue. I encourage it, and support local efforts. If you're the type of family/person that can take in a rescue. Not everyone can, or feels they are able to cope. I would not encourage a first time pet owner, or someone unable or willing to put the work in to recuse. They can be a lot of work, although very rewarding.
I don't think it's wrong to purchase a well bred dog (normally a pup) from a responsible breeder. They do tend to cost more, but it's worth it. For my current breed, the Shih Tzu, you can by a pup from a byb or a puppy mill for $400 and a responisble breeder will probly run around $1000. I would definately spend the extra. The responsible breeder charging $1000 has health tested the parents, run genetiv tests, has shown the parents, taken all possible steps to ensure the health of their pups. So I'd rather spend the extra, because I'm sure to save it in vet bills later. Not all of them do it (there are byb's and mills that charge that much to make them look reputable), but if you look and ask the right questions, it's worth it.
Anyway back to the fish. Molly and Berry seem to be doing well. They swim around, very energetically, and play with one another. They are a pleasure to watch. The only thing is I never see Berry (the Tetra) eat. Molly is in to a routine and circles the area of the tank where I deposit the food when it's time for feeding, as it's typically at the same time every day. but I Berry doesn't. Not that it's terrbile disturbing. But I don't see her come up to eat at all. How long can they go without eating? Should I be worried? Am I just missing her eat?