Before diving into choosing the best beginner fish for your new tank, we should cover some basic industry terms and categories used in the aquarium industry that help people to choose and care for fish properly. These terms will not only help you choose the right fish but also help you understand the needs of your fish and achieve success in caring for them. 

1. Temperament

All aquarium fish are going to fall into these three categories that describe their temperament and level of aggression toward other fish. Just remember, this is not black and white and fish do have personality meaning they might fall into more than one category simply based on what side of the bed they woke up on!  This can help you decide which fish can safely be housed together. 


These fish are not aggressively territorial, will not eat other fish, and generally speaking, can safely be housed alongside other community fish. 


This is the largest group of saltwater fish. They are territorial and should only be stocked with other semi-aggressive fish. They are generally not predators and will not eat other fish, they simply defend their territory against intruders. 


The predators. These are the most aggressive and will actively hunt and eat their tankmates. They may also be highly territorial. Stocking with other species should be done quite carefully, only stocking alongside other fish they would not consider prey. 2. Habitat

2. Habitat

This describes the part of the aquarium the fish will live based on its natural habitat. For example, some fish feed and swim throughout the upper part of the water column, free-swimming above the rocks. Some fish like to live in the sand, some prefer to hide in the rocks. We can generally break it up into three basic habitats as found in our aquariums. Think of this as filling the different niches in your tank and you have to spread things out among all of the three niches. 

Free Swimmers

These fish often school together, finding security in numbers because they don't really hide. They will inhabit the upper part of your water column, above the rocks. They are always out and about where you can see them as well. Chromis, Cardinalfish and Anthias are good examples. 

Sand Bed Dwellers

Self-explanatory, these fish like the sand. They will burrow or create nests down inside the sand bed. Gobies and Wrasses are the most common examples

Rock Dwellers

These fish prefer holes, overhangs, arches, and crevices in or around the aquascape. These fish spend a majority of their time hiding but will come out to eat and protect their territory. Some of these fish will find a hole or crevice and live inside the rocks while others, like clownfish, will relate to a particular piece/area of structure and protect that as their territory.

3. Reef Compatibility

This describes how suitable the fish is for living in a reef tank.  Does it eat corals? Will it eat snails? A fish that is not reef-safe generally should not be housed with invertebrates or corals.  

Reef Safe

Won't eat corals. Safe for housing in a reef tank with living corals.  Clownfish, damsels, gobies, cardinalfish, anthias, and tangs are common reef-safe fish.

Reef Safe With Caution

The most confusing of the categories. These fish may or may not eat coral. It really just depends on whether or not that particular fish has developed a taste for coral. Some hobbyists believe it's simply about the availability of food and if you feed the fish enough, it won't go after coral. In some cases, eating coral is a learned trait so only a mature wild-collected specimen will have the tendency to eat corals.  Dwarf Angelfish are a good example; many of the captive-bred Centropyge "Dwarf" angels won't touch coral while their wild collected counterparts do. 

Not Reef Safe

Fish that eat corals, not suitable for a reef tank with living corals. 

Fish That Eat Inverts

These fish prey upon snails, crabs, and shrimp but won't technically eat living corals. That means they can live in a reef tank, but you might have to restock your clean up crew on a regular cycle.  

9 Characteristics Of Beginner Saltwater Fish

So now that you know how to classify saltwater fish and are prepared for some of the terminologies you're going to encounter at your local fish store, let's talk about the characteristics you should look out for when choosing a beginner Fish. 

1. Hardiness - Choose hardy fish that can handle some level of stress.

2. Inexpensive - Don't buy expensive fish your first time around.

3. Easy To Find - Choose fish that are commonly available at your LFS.

4. Acclimates Well - You want something that acclimates well into an aquarium.

5. Ships Well - Choose fish that have a good survivability rate in terms of shipping. 

6. Captive Bred - Captive-bred fish are always a more responsible and smarter choice. 

7. Small - Sticking with small fish means you can buy more of them.  Bigger fish are simply more demanding.

8. Peaceful - Avoid problems associated with aggressive fish; this can be really frustrating for first-time tank owners. Stick to the community and semi-aggressive category.

9. Accepts Prepared Foods - Finicky eaters are always going to be more sensitive in an aquarium. Avoid fish that have specialized diets because they are more demanding.