Long-Whiskered Catfish

Catfish don´t have long whiskers for looks. They are there to help them hunt for their food - other fish! In addition to eating all fish of less than half their size in the tank, many of the piscivorous (fish-eating) Cats will outgrow most tanks. One common species of long-whiskered catfish, the Pictus Cat - Pimelodus pictus grows to 10" while the Channel Cat (a pink form is often seen) grows over 2 feet long. Shovelnose Cats are usually only seen at six inches or greater, so the beginner does have some warning with these. Still, one might not expect them to get 2 or 3´ long.

Bala Shark

Not a shark at all but a Cyprinid (related to the Carp), Bala Sharks - Balantiocheilus melanopterus quickly outgrow most home aquaria. They get to be over one foot long.

Red-Tailed Catfish

Red-Tailed Catfish - Phractocephalus hemiliopterus are particularly large-growing predatory catfish. A dark body with a horizontal white stripe and red tail gives them an attractive appearance at a small size that has unfortunately made them a popular aquarium fish with those who fail to appreciate the enormity of adults. Adults may grow to well over 4´ in length and have mouths that more than match their lengths. As such, they are more than many public aquaria can house, not to mention private aquarists.

Plecos

The suckermouth catfish of the genus Hypostomus are often sold in the stores as algae cleaners. Most of these species get in excess of 12". Some of the slender suckermouth catfish, such as the Whiptail - Dasyloricaria filamentosa and the Farlowella - Farlowella gracilis, are quite delicate species

Piranhas

Piranhas are among the most abused of all aquarium fish. They are often purchased in order to watch their legendary feeding habits. As mentioned above, feeder fish often bring diseases and parasites with them and these can infect Piranhas. A regular diet of feeder fish can also be quite expensive.
Piranhas are schooling fish and are generally shy and stressed when kept as single specimens. Unfortunately, they also get big (many species well over a foot long), so most beginning aquarists don´t have room to house more than a single Piranha. If enough tank space is available to keep several Piranhas together, they must be kept well fed or they will turn on each other, killing and cannibalizing one fish after another.

Glass Catfish

Another catfish to avoid is the Glass Catfish - Kryptopterus bicirrhis. While it stays small enough to be an aquarium fish (up to 6"), it is very delicate and should not be purchased by beginners.

Dyed Fish

While Painted Glassfish were for a long time the only fish commonly seen that had been colorized by unscrupulous marketers, the last few years have seen several other fishes subjected to this abuse. One of these is the White Skirt Tetra (an albino version of the Black Skirt Tetra - Gymnocorymbus ternetzi) which are sold as Blueberry Tetras, Strawberry Tetras, Rainbow Tetras, etc. depending on the dyes used to color the individuals. Similarly, Blueberry and Strawberry Loaches have also been seen. If you are unsure if a fish has been dyed, ask.

Spiny Eels

Spiny Eels (family Mastacembelidae) are aggressive fish, some of which grow quite large (over 3´). Some do stay small (less than 4" for one species), but all are likely to have internal parasites.

Knife Fishes

There are several families of fish from South America, Africa, and Asia, referred to as Knife Fishes. Many species of Knives get large, some over 3´ long although some of the less attractive species stay as small as 8". All of them are nocturnal predators, a fact that many a beginner could have used before all of his or her small fish mysteriously disappeared a few at a time.

Painted Glassfish

Painted Glassfish are Glassfish - Chanda ranga which have been ``painted´´ with chemical dyes. This procedure adds a temporary bit of unnatural color (which disappears with time) and stresses the fish, causing them to be prone to diseases and parasites. This fish needs at least 1 teaspoon of salt per gallon of aquarium water

Rasboras

The most popular Rasbora is the Harlequin Rasbora - Rasbora heteromorpha. A very similar looking species, Rasbora espei, is also available, as is the Clown Rasbora - Rasbora kalochroma and the ScissorTail Rasbora - Rasbora trilineata. Orange, brown, and red are usual colors for Rasboras, and their stop-and-start swimming makes them interesting to watch as a school. ScissorTails can get up to 6" long and Clown Rasboras up to 4" while Harlequins stay under 2" long.
Family: Cyprinidae

White Cloud Mountain Minnows

``White Cloud Mountain Minnows´´ - Tanichthys albonubes
Found in mountain streams in China, White Clouds can be kept in unheated tanks (down to 55F). Some people advise against putting these fish in tropical tanks but I have found that they do fine in heated aquarium as well, as long as the temperature is not kept above the mid 70s. They can be fed any small food and they spawn often but fry will not be seen unless the parents are removed to another tank. White Clouds are brown with a red tail and a silvery white line down the side that shines in the light. They get to be 1 1/2" long.
Family: Cyprinidae

Corydoras Catfish

Cory Cats are members of the family Callichthyidae, a family of armored catfish from South America. Corys are small (generally 2 1/2" long or less), schooling fish that are always searching the bottom of the tank for food. There are at least 140 species of catfish in the genus Corydoras. Some of these are quite delicate and die quickly even in the hands of experts. The fragile ones, however, are rarely seen in pet stores and are high priced when they can be found. Corys generally feed at the bottom of the tank and special sinking foods should be fed. These include sinking pellets like Tabi-Min and frozen blood- worms. Care should be taken to insure that all frozen foods are eaten quickly as they decay rapidly and can foul the tank. Don´t overfeed!

Goldfish - The Basics

Goldfish are one of the most common fish sold to beginners, but are particularly poorly suited to this role. The common Goldfish sold as feeders are generally full of diseases and parasites which may kill them and other fish they are housed with. Fancy varieties, which have been selectively bred for centuries to achieve their unnatural appearances, are subject to a host of problems associated with their abnormalities.
All Goldfish are cold water fish which do not do well in the lower oxygen levels found in tropical aquaria, and therefore should not be housed with tropical species.

Hatchet and Pencil Fishes

Somewhat related to Tetras, Hatchets (family Gasteropelecidae) and Pencils (genus Nannostomus) are Characins from South America. Many of them need soft and acid water and all of them are delicate. Hatchets have the added disadvantage that they tend to launch themselves out of the aquarium to an untimely death.

Iridescent Shark

Iridescent Shark
Unrelated to the Bala Shark or to true sharks, the Iridescent Shark - Pangasius sutchi is a catfish. It grows to over 3´ and tends to injure its nose against the aquarium glass.

Danios

Several species of Danios are often found in pet stores, including the Giant Danio - Danio aequipinnatus, the Zebra Danio - Brachydanio rerio, the Leopard Danio - Brachydanio frankei, and the Pearl Danio - Brachydanio albolineatus. These fish are fast swimmers and are always in motion. Different patterns of blue markings allow one to tell these fish apart. Most Danios stay under 2 1/2" long, although Giant Danios can get up to 4".
Family: Cyprinidae

Elephant Nose and Baby Whale

More fragile fish include Elephant Noses - Gnathonemus petersi and Baby Whales - Petrocephalus bovei. African fishes from the family Mormyridae, these are night feeders and are hard to provide for in the aquarium.

Cyprinids

White Clouds, Danios, Rasboras, and Barbs are all Asian fish related to the Carp and the Minnow. All of these fish belong to the family Cyprinidae. White Clouds, Danios, Rasboras, and Barbs are small, active, hardy, and colorful.