Marine fish are fish that are able to flourish within an aquarium that is saltwater-based. The size and the shape of the aquarium will help to determine the types of fish that are able to live and thrive within that particular environment. While some fish are small and will not grow much larger than they are when purchased, others can grow to greater lengths and will therefore require more space in their living environment. When purchasing marine fish, buyers must also consider the types of fish, if any, that they already own. Many fish are unable to cohabitate with other types of fish and must be kept in their own environment. In order to assist readers in buying marine fish, this guide discusses popular types of marine fish and their particular needs, it provides insight into the different aquarium sizes, it educates buyers on how to properly clean and maintain an aquarium environment, and it provides instruction on how to search for and purchase marine fish at retailers such as pet stores and eBay.

Popular Types of Marine Fish

There are many types of marine fish that can be differentiated by the type of food that they eat, by the environment and level of care they require, as well as by the amount of space that is needed to keep them in good health.


Angelfish are able to easily adapt to a wide array of environments, although their size often requires a buyer to invest in a larger aquarium. These fish are able to cohabitate with other angelfish as long as they are introduced to the aquarium early in life and have different coloring and body shape from the other fish. However, due to their diet, only those owners that are familiar with the needs of angelfish should consider combining them. In general, angelfish incorporate large amounts of vegetable matter into their diets.


Blennies are popular type of marine fish that features a single dorsal fin that runs the length of their body. They possess a peaceful nature and a colorful design. Blennies are considered omnivores and feed on algae, along with frozen or live food. Because blennies do not have teeth, their food must be small enough for them to swallow entirely. Most blennies, with the exception of fang blennies, prefer a reef environment where they can hide.

Cardinal Fish

Cardinal fish are nocturnal and tend to possess a shy demeanor. These fish feed on meaty foods and often reject fish flakes or tablets. Other than their somewhat temperamental diet, cardinal fish are fairly low maintenance fish and are not particular about their living environment. In order to provide proper care, buyers should keep an eye on ammonia or nitrate levels in the aquarium’s water, as cardinal fish are sensitive to these chemicals.


Clownfish are a popular type of marine fish that many buyers may recognize from the popular Pixar film, “Finding Nemo.” They are attractive and are able to easily adapt to their surroundings. Clownfish best flourish with a host and are commonly paired with sea anemones. Unlike the clownfish themselves, sea anemones require specialized care and high levels of light in order to survive. Because of this, many buyers may avoid using a sea anemone as a host, instead choosing to use coral or feather duster worms for that purpose.


Scorpionfish are relatively small and are fairly inactive. Because of this, these fish are able to flourish in smaller-sized aquariums. Scorpionfish feed on live food and are capable of eating fish that are quite large. Buyers should take caution when approaching these fish, as they are venomous.


Tangs typically feed on algae, although some species are carnivorous. These fish are temperamental and do not flourish well when they are placed in an aquarium with similarly shaped or colored fish. Tangs feature a spine on their tails that allows them to cut other fish open. The spine can also cut an owner’s hand if proper precautions are not taken. These fish are an active breed and require adequate swimming room in an aquarium.


Although some triggerfish make great reef fish, most are temperamental and feed on invertebrates. Certain types, such as the undulated trigger and the clown trigger, must be kept separate from other aquarium inhabitants because of their aggressive demeanor. These fish require large aquariums with good filtration systems.