Eric is an aquarium enthusiast with over two decades of experience caring for a wide array of tropical fish.
When you are new to the aquarium hobby, you have a lot to learn. Not only do you need to figure out the best practices for tank care and management, but you also have to add a whole bunch of new words to your vocabulary. Many of those words are the names of the fish themselves, and understanding who is who in the aquarium world can help you make better decisions.
Stepping into any live-fish store tells you this is a daunting process. There are hundreds if not thousands of fish species available in the aquarium industry. How are you supposed to remember their names, let alone their traits, and the best ways to keep them happy and healthy?
It helps to be able to organize them by type. Related fish often (but not always) exhibit similar characteristics and behaviors. Once you get a handle of what type of fish you are looking at, you can surmise what you can expect from them.
All of these fish have official, scientific names and can be organized by family, genus, and species. That’s not what this article is all about, but I encourage you to research those names on your own if you wish.
Instead, I'll be using terms you'll see frequently as you learn more about fish keeping. You aren’t likely to encounter the name Characin unless you look for it, but chances are you’re going to see the name tetra quite a bit.
So, which common fish species fall under the type tetra, and what are their typical traits? Read on to learn about that, and more.
Tetras are small, colorful fish that typically should be kept in groups of six or more. They are shoaling fish in the wild, as a large group helps to reduce stress.
The most common tetra found in pet stores is the neon tetra. They only grow to an inch or two in length as adults and have a vibrant blue and red coloring. They are among the best fish for a 10-gallon tank but kept in large schools in a big, planted tank they look truly spectacular.
Other tetras you may see include:
- Black neon
- Cardinal tetra
- Congo tetra
- Buenos Aires tetra
- Rummy-nose tetra
Some grow to a few inches in length, and may be better a better choice in tanks with large fish.
When planning your stock it is a great idea to have at least one shoaling fish, such as a school of tetras. From an aesthetic perspective, they help to provide a backdrop of color and movement for your larger centerpiece fish.
Anabantids, or labyrinth fish, are able to take gulps of air at the water surface in addition to breathing through their gills. If you’re thinking you’ve never seen one before, I bet you’re wrong!
Betta fish are anabantids. When the oxygen in the water gets low, they can survive. But be aware that this is an adaptation they evolved in order to stay alive long enough to breed, not an excuse to keep them in sub-par conditions in the home aquarium.
Gouramis are anabantids too. Dwarf gourami and larger species such as the three-spot gourami are common fish in the aquarium industry.
The leopard bush fish is one more you might encounter in the fish store. These guys are among my favorite fish, but be aware they may eat anything that fits in their mouth!
All three of these anabantids can have tank mates, including betta fish. But because of their unique and sometimes difficult care requirements, I suggest doing diligent research before choosing them for a community tank. In my experience, it is also a bad idea to keep them together.
3. African Cichlids
African cichlids are at the top of the list of the most colorful freshwater fish you are going to find. If you have always wanted a beautiful reef setup but don't think you can deal with managing a marine tank, these guys may be the right choice for you.
They come from huge lakes in Africa, and there is a wide range of different species. Some are peaceful, but they are typically aggressive and territorial and exhibit some difficult behaviors.
That doesn’t mean you should avoid them. It does mean you need to do a lot of research before you decide to keep African cichlids. They shouldn’t live with other tropical fish, and they require large tanks, particularly with a large footprint.
A well maintained African cichlid tank can be beautiful. Just be sure to learn as much as you can about them before jumping into their world.
4. New-World Cichlids
New-world cichlids, sometimes called South American cichlids, come from South and Central America, as their name suggests. They are not compatible with African cichlids, but they may be compatible with many of the other fish listed in this article.
As with African cichlids, there are many, many species of new-world cichlids, and they range from docile to very aggressive.
The freshwater angelfish is one of the most popular. While they are typically listed as semi-aggressive and may even eat small fish, kept correctly they can be amazing centerpiece fish in a tropical tank.
So can the discus fish, the angel’s pricier and more colorful relative. Other popular new-world cichlids include the oscar, firemouth, Jack Dempsey, convict cichlid, and German blue ram.
The name barb incorporates a wide range of colorful fish. While they may be good community fish, many have a reputation as semi-aggressive fin nippers. I've always kept them in tanks with larger, somewhat aggressive tank mates, and avoided them in docile community setups.
There are few types of barbs you will commonly come into contact with in the aquarium hobby. One is the tinfoil barb. These stunning silver fish seem like a good choice when they are small, but they can grow to an adult length of a foot or more.
Tiger barbs and cherry barbs are better for tanks under 75 gallons. They’re shoaling fish, so keep them in small groups.
The term catfish is used very broadly in the aquarium industry and describes a number of bottom-dwelling, scavenger-type fish. These include:
- Corydoras: Cories are shoaling fish that come in many varieties. These hard-working little guys make great custodians for your tank.
- Plecostomus: Plecos are the “suckerfish” you see stuck to the glass of tanks, eating algae. Most species grow way too large for the average home aquarium.
- Otocinclus: Sometimes called the “dwarf suckerfish”, otos are my favorite algae eaters and they are appropriate for any tank over ten gallons.
- Iridescent Shark: If you think plecos grow to stupid-big sizes, check this fish out. Iridescent shark catfish may reach an adult length of up to four feet! If you are thinking of getting them, don’t.
Any time you add bottom feeders or algae eaters to your tank you want to be sure to feed sinking pellets and algae wafers. While they can and will scavenge food and algae on their own, supplementing their diet ensures they are getting the proper nutrition.
Loaches are bottom-dwelling scavengers, and there is a wide range of sizes and species available for the home aquarium. One of the most common is the clown loach, a fish many claim can help you clean up your pest snail problem. However, they need to be kept in schools and can grow to a foot long in some cases. They are big fish, and unless you have a very large aquarium, you should probably give them a pass.
The kuhli loach is another popular fish, and more appropriate for smaller aquariums. They look like little eels, with striped, elongated bodies. These scavengers like to come out at night and tend to hide in the day.
The yoyo loach is a medium-sized fish, and a small school is a good choice for a 55-gallon tank or bigger. They are smaller than clown loaches, and more visible that kuhlis.
Some of the most popular freshwater aquarium fish are livebearers. Instead of laying eggs, they give birth to tiny versions of themselves.
Livebearers include common species like guppies, platies, swordtails, Endlers, and mollies. When stocking these fish it is smart to plan two females for each male. In other words, stock them in groups of three. This cuts down on stress in the tank and ensures the females are not overly harassed.
Keeping livebearers means you may awaken one morning to find a bunch of fry in your tank. If you intend to raise them be wary: Other fish will eat them if they can. There are special nets you use to keep them safe, but some breeders prefer to simply provide plenty of plants and other decorations so the fry can hide.
Along with African and new-world cichlids, killifish are some of the most vibrant fish you can add to a freshwater aquarium. There is a wide range of species, in many sizes and colorations. Some make great community tank fish when kept with other types of fish, but some fish keepers manage killifish-only tanks.
While killifish are typically hardy, they are typically not mentioned among the best tropical fish for beginners. One reason is that they are not quite as common as most of the other fish mentioned in this article. Choosing fish through mail order is best left to experienced aquarists.
Many people consider white cloud mountain minnows for their freshwater aquariums. They are a great choice for newbies, and quite hardy. However, white clouds aren’t tropical fish. They thrive in cooler water and therefore aren’t appropriate for tropical tanks. But, for those looking to avoid using a heater in their tank they might be a good option.
The popular zebra danio is another hardy fish that’s great for beginners. They aren’t really “tropical” fish either but can do well in tropical temperatures.
The harlequin rasbora is another you may encounter. Like other minnows, they should be kept in schools of six or more.
Some related species may surprise you. Bala sharks are in this family. These fish are sold in pet stores as cute two-inch-long juveniles, but they grow to around a foot and need to be kept in schools.
Stocking Your Freshwater Aquarium
Understanding what to expect from different types of tropical fish can go a long way toward making smart choices when stocking your tank. Even so, you’ve probably noticed some fish with behaviors that swing wildly away from many of their relatives.
This is why I still advise you to do more in-depth research on individual species you'd like in your tank. There is no substitute for doing the homework necessary to understand the fish you intend to stock, and there is no shortcut.
Like any hobby, there is a lot to learn in aquarium care. The difference is that the price of mistakes can mean the death of live animals, and frustration for new fish keepers.
That's always a horrible experience when fish die, but it happens to all of us. All you can do is gather as much knowledge as possible, and make the best decisions you can. Knowing the different types of fish is a good start.