Predators

So far we've covered quite a few fish. However, there are certainly more. The fish covered in this section are not well suited for the beginner's aquarium for a number of reasons. Some may be highly sensitive to fluctuating water quality conditions, a frequent problem in a new aquarium. Others may require special water conditions, such as softer water or brackish water. The beginner should not try to provide this type of habitat without acquiring some experience.

Finally, there are a number of species that are not socially compatible with the peaceful community tank. This group includes large carnivorous fish that eat smaller fish, territorial fish that do not tolerate trespassing, and mature fish that display aggression and combative behavior during spawning or pre-spawning periods. In short, you have to know what you're doing if you want to handle one of these bad boys.

Many of these species are offered by the pet store and may even be promoted by the dealer because they are smaller juveniles that he considers “harmless.” Don't be fooled by this argument. These fish grow fast and develop aggressive attitudes early in life. The small flake-eating baby will become a neon-eating carnivore in a matter of months.

Do not buy fish that require special water conditions. Beginners are usually not equipped to handle these requirements. These fish may live for days or weeks in your tank, but chronic stress will set in, and its immune response will fail. Ultimately, the fish will die due to disease.

As a novice, you must avoid the following fish. Here is a brief description of those species that should not be included in your community aquarium. As you develop your talents as an aquarist, you will expand your capabilities, and be able to keep some of the more sensitive species of fish. You may even want to establish an aquarium of “compatible” aggressive species or a species tank. As you will notice, many of these fish are cichlids.

Green Discus Symphysodon aequifasciatus

Origin: Amazon

Size: 6 inches

Food: Carnivorous

Temperature: 79-86°F

The green discus are outright beautiful fish. This very peaceful fish would be an attractive addition to the community tank. In the end, it really is best kept in a species aquarium. Why? Because it requires soft acidic water and becomes territorial when breeding. As aggressive as the discus can be, it falls into an unusual spot. It is too aggressive for most community tanks, and is not aggressive enough to be kept with the following fish.

Oscar Astronotus ocellatus

Origin: South America

Size: 13 inches

Food: Carnivorous

Temperature: 72-77°F

Oscars are often sold when they are very young and unassuming. However, you have just bought Frankenstein. They grow quickly. And they grow very large, given enough space. They can also be aggressive and they are quite strong. We once saw an oscar pull a large net right out of a hobbyist's hand. They require small fish or meaty food to satisfy their hefty appetites. Common goldfish, sometimes called feeder goldfish (because they are bought by the dozen), are a common food for domesticated oscars. Otherwise, they can tolerate a wide range of water quality parameters.

Red Devil Amphilophus labiatus

Origin: Central America

Size: 10 inches

Food: Omnivorous

Temperature: 75-79°F

The red devil, a cichlid, is an aggressive territorial fish that will eat anything and everything. This species can only be mixed with species that can take care of themselves, like the large oscar, Jack Dempseys, and jewel cichlids. They cannot be kept with discus.

RED DEVIL

Jewel Cichlid Hemichromis bimaculatus

Origin: Central Liberia to Southern Guinea

Size: 6 inches

Food: Omnivorous

Temperature: 70-73°F

The jewel cichlid is noted for its extremely aggressive behavior when breeding. This belligerent fish will establish a territory and aggressively protect it.

JEWEL CHICLID

Jack Dempsey Nandopsis octofasciatus

Origin: Central America

Size: 8 inches

Food: Omnivorous

Temperature: 72-77°F

The Jack Dempsey is another of the cichlid species that is intolerant of other species. The Jack Dempsey belongs in a species aquarium; otherwise, it will incessantly harass other species.

Rummy-Nose Tetra Hemigrammus bleheri

Origin: Colombia, Brazil

Size: 2 inches

Food: Omnivorous

Temperature: 72-79°F

This species of tetra is highly sensitive to water quality conditions. Any buildup of nitrates will cause chronic stress and ultimately lead to disease and illness.

Tinfoil Barb Barbus schwanefeldi

Origin: Southeast Asia

Size: 14 inches

Food: Omnivorous

Temperature: 72-77°F

The tinfoil barb is often mistakenly recommended by retailers as community fish. They are not. These fish are very active and grow far too large for the average aquarium. They require a lot of space, are best kept in schools, and have a tendency to dig up the substrate.

Sucking Loach Gyrinocheilus aymonieri

Origin: India, Thailand

Size: 11 inches

Food: Herbivorous

Temperature: 77-82°F

Most loaches are algae eaters. That's why we like ‘em. However, this species can be aggressive toward its tank mates. And it becomes territorial as it gets larger! Its large size also precludes inclusion in the community tank.

Red Snakehead Channa micropeltes

Origin: India, Burma, Thailand, Vietnam, Malaysia

Size: 39 inches

Food: Carnivorous

Temperature: 77–82°F

This is another monster. These are for serious aquarists only. This large carnivore requires warm temperatures and small live fish to feed on. Although juveniles are considered “cute,” they grow rapidly and consume the community.

Mudskipper Periophthalmus barbarus

Origin: Africa, Southeast Asia, Australia

Size: 6 inches

Food: Carnivorous

Temperature: 77-86°F

The mudskipper is becoming increasingly more popular in the aquarium trade. The problem with this fish is that it requires brackish water, which it needs to leave periodically. These requirements make this a challenge, even for experienced aquarists. Its territorial nature can also be a problem.

Clown Knife Fish Notopterus chitala

Origin: Southeast Asia

Size: 39 inches

Food: Omnivorous

Temperature: 75-82°F

The knife fishes usually become too large for the average community aquarium. This species and its relatives can be extremely aggressive and are best kept alone or with other large fishes.

Arowana Osteoglossum bicirrhosum

Origin: Amazon

Size: 47 inches

Food: Carnivorous

Temperature: 75-82°F

The arowana is an elegant and menacing fish that enchants the novice as well as the expert aquarist. It is a predator of the highest rank. Its large size and predatory nature exclude it from the community aquarium. Many arowana are kept alone in large tanks.

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