Fish Species at

Printer Friendly

Seven Families of Aquarium Fish

Learn about the seven families of aquarium fish.

By Mike Nolan

Page 2 of 3

The Tetras
Picture a neon tetra, a black tetra, a lemon tetra, a cardinal tetra. The tetras are all members of a family called Characidae. They and members of several closely related families come from South America and tropical Africa. There are several hundred different species. In general, these fish are small, ranging from 1 to approximately 2 inches in length. They are active swimmers and spend their time in the upper half of the aquarium.

The tetras offer fairly bright colors, with silver, black and shades of red predominating. They display best in a small school in tanks with a large open area in front and some plants in the background. They accept all standard aquarium fare and are very competitive eaters. A varied diet is best, of course.

The tetras will coexist with most other fish who cannot have them for lunch. Except for breeding, the tetras do not require any special water conditions. Given proper water conditions and food, most of the tetras are easily bred. However, their fry are very difficult to raise, requiring very small food and very sanitary conditions. These requirements usually preclude all but advanced aquarists from rearing the young.

In summary, for active color in the mid to upper levels of a tank, any member of this group is an ideal choice. For best effect and normal behavior, a school of six or more of the same kind works better than one or two each of several different kinds.

The Barbs
The fish known as the barbs are a subset of a group of fish commonly referred to as the carps and barbs. They all represent members of the family Cyprinidae. These fish are somewhat similar to the tetras. Most of the barbs are stockier and larger than the tetras, with many in the 2- to 4-inch range, although a few get considerably larger.

Typical of the most common representatives are the cherry barb, the rosy barb and the tiger barb. The best known of the large members is the tinfoil barb. These fish are less colorful than the tetras but are larger and show up better from a distance. The predominant colors are silver and gold with some black and red highlights.

To discern the difference between barbs and tetras, look for the stockier fish with a coarser appearance (due to larger scales). Also, most of the Cyprinidae have barbels. These are small whiskers on the lower jaw of the fish. In addition, barbs do not have an adipose fin, whereas the charicins all do. The adipose fin is a small "flesh-like" fin on top of the fish behind the dorsal fin. Also included in the Cyprinidae family are the danios and rasboras. While these could be mistaken for members of the characins, their maintenance is the same as the barbs.

The barbs are active swimmers and prefer the upper areas of the tank. Although not as strongly inclined to school as the tetras, they do appreciate the company of their own kind. They will thrive in a wide range of water conditions. Like the tetras, these fish will accept all standard aquarium foods.

The barbs can be induced to spawn under aquarium conditions. They scatter their eggs in fine-leaved plants. The parents will promptly eat the eggs, however, and normally some provision must be made to prevent this from happening. The fry are considerably larger than those of the tetras, and therefore are much easier to raise. They are a good choice for your first attempt at breeding fish if you are so inclined. A particularly good choice would be the zebra danio.

Goldfish are a colder water member of this group that have been breed in captivity for many, many generations to develop the numerous variations of shape, color and finnage available today. Because goldfish are not tropical fish, they should never be kept with warmer water species.

The Catfish
Everybody knows what catfish are — they have whiskers, right? Actually, yes, the distinguishing feature of catfish is that they have barbels (whiskers). In most, but not all, catfish, these barbels are quite prominent and readily noticeable. The other distinguishing characteristic of catfish is that they do not have scales.

You probably thought all fish had scales. And you might ask, "What is that I see on the sides of my Corydoras?" The fact is, no catfish has scales. Many have bony plates that look like large scales, but some do not have even these. The coloration of most catfish is restricted to shades of brown, black and white. There are a few spectacularly colored exceptions.

Many people consider catfish to be ugly or weird in appearance and a necessary evil as scavengers. Fortunately, this outdated viewpoint is fading and people are starting to appreciate catfish in their own right.

The catfish belong to not one but 32 different families, the vast majority of which come from freshwater environments. They inhabit every continent except Antarctica. They are also the most diversified of our groups. There are more than 2000 different species. They range in size from less than an inch to several feet. However, the majority of those available at reasonable prices tend to be from 2 to 6 inches when full grown. Most are bottom fish. That is, they will spend the majority of their time on the bottom and will actively search for food using those whiskers. Some are nocturnal and therefore active only at night.

In selecting catfish for your tank, the most important consideration is whether or not they will get along with the other residents. Although catfish are less likely to be eaten than many other fish, it is not impossible if there is enough of a size difference. Another consideration is whether the catfish will reverse the situation and eat their tankmates. Many catfish are piscivorous, meaning they are "fish eaters." To determine their feeding preferences, look at the mouth of each species. If it is pointing downward or is a sucker mouth, you are probably safe. If, however, the mouth is large and/or points forward, beware! Predatory catfish are not to be trusted in a community tank. For example, there is a common fish, sold as an "angelicus catfish," that is silver with black stripes. It is very striking in appearance. Many are sold as being harmless. As long as they are small, this is true. But they grow fast and at 3 or 4 inches will eat any fish they can catch, up to three-quarters of their own size.

Catfish are not fussy eaters, but neither should they be neglected and just allowed to scavenge off the remains left by the other fish. Although often sold as scavengers for community tanks, catfish require the same nutritious foods that other aquarium fish need. Feed your catfish with food that sinks to the bottom of the tank and they will reward you with many hours of pleasure, for they are very long lived and hardy. Many of the catfish can be bred in aquariums, and some are raised in huge quantities commercially. Others, however, have never been bred in captivity. Next Page>>

Page 1, 2, 3

 Give us your opinion on
Seven Families of Aquarium Fish

Submit a Comment   Join Club
Earn 1,000 points! What's this?
Reader Comments

Ryan    sarasota, FL

5/3/2009 5:15:35 AM


View Current Comments

Top Products