When you buy through our links, Insider may earn an affiliate commission. Learn more. Fish tanks are living ecosystems that are beautiful to look at and rewarding to maintain. The hobby can be an expensive one, though, so it's important to understand the requirements of the fish species you're interested in before purchasing a bunch of equipment. Different fish have different needs for tanks, filters, and lights. For example, some fish are freshwater natives while others live in saltwater. There are also fish that prefer cold water to warm. In addition, different fish thrive in tanks of different sizes. If you are new to fishkeeping, it can be daunting to find the right products for an ideal fish tank habitat. To learn about the essential qualities of aquariums, fish tank filters, and lights, we spoke with four people who are experienced in aquascaping and fish care. With their advice in mind, we combed through the aquarium equipment available at major