Are there any fish that don't die easily?

Yes, In general coldwater fish like goldfish are more hardy(harder to kill) than tropical fish. Saltwater Fish are very easy to kill if you don't know what you are doing. Goldfish are very hardy fish that you can't kill easily. It is best to start out with fish like goldfish because you can make mistakes with them that would kill other fish. So goldfish are fish that does not die easily.