Hi, I'm currently in the looks for a fish. This would be my first real fish, not just a family goldfish. I've visited several stores near my home and most of the workers don't know much about fish, and other websites contradict each other on life-spans and gallon requirements. Hopefully, you guys with personal experience could assist me? In my house, I have a slot inside my wall for a small aquarium, originally used for an in-wall safe. I can fit up to a 5-gallon fish tank within the wall. All I need is a fish. I want to get one really beautiful and preferably exotic fish. I have no budget for the fish or its setup, just a few requirements. It must be okay with being alone and in a 5-gallon tank and feel comfortable and happy with its space, I don't want it becoming depressed and sad. It must also have a long lifespan, I don't want to buy an expensive fish for it to die of old age within the first 2 years. I'm looking for a friend that will last. It's preferable if the fish is low maintenance, but I don't mind getting my hands dirty to keep him happy. Thank you!