Beginners Guide - Tetras.

Like many of the fish in the first section, Tetras are schooling fish and should be kept in groups of six or more of the same species.

Tetras are native to Central and South America and Africa. In some regions of South America the water is quite soft (very little rock is dissolved in it) and acidic. (Another way of saying "acidic'' is to say that it has a low pH - one below 7, which is considered "neutral''. A strong acid has a very low pH. Liquids above pH 7 are said to be "basic''.)

Unless you know that your tank water is also soft and acidic, the Tetras that need that water should be avoided. Before you buy a Tetra that you are not sure about, look it up in your book. If it says that it needs a pH below 6.5 you should probably avoid it.

While many beginning aquarists are tempted to simply adjust the pH of their water by buying little containers of chemicals in the pet store, do not give in to this temptation! Water chemistry is very complex and you can easily kill all your fish by trying it. On the other hand, if your tap water is naturally soft and achieves a consistent acidic pH, there is no reason that you can't try your hand at some of these fish.

Two very popular Tetras which need soft, acidic water are the Neon Tetra - Paracheirodon innesi and the Cardinal Tetra - Cheirodon axelrodi. These are quite attractive red and blue fish. The red line on the Cardinal runs from the head on back, while in the Neon it starts only in the belly region.

Besides its water requirements the Neon has the added drawback that almost all of them are bred in the Far East in huge numbers with no regard to quality. Further, the raising ponds for the young fish are filled with medicines. The medicines keep diseases in check but as soon as the fish are shipped they begin to get sick. They die in huge numbers in the shops and in buyer's home tanks.

Probably less than 1 in 10 Neons lives for more than one month after being removed from the pond it was raised in. Further more those two or three tiny neons you purchased from your local shop can easily introduce a disease that kills all the fish in your tank.

Cardinals will have a greater chance of not dying immediately after purchase but even they will probably not live long in your home tank. They are wild caught in Brazil as adults so they may have lived most of their naturally short life span before you buy them.

Other Tetras which need acidic water include the Blue Neon Tetra - Hyphessobrycon simulans, the Flag Tetra - H. heterorhabdus, H. metae, the Loreto Tetra - H. loretoensis, the Black Phantom Tetra - Megalamphodus megalopterus, and the Red Phantom Tetra - M. sweglesi.

So what about those aquarists without acid water?
There are plenty of hardy Tetras out there for beginners without special water. These include the distinctive Black or Black Skirt Tetra - ymnocorymbus ternetzi, the brightly colored Glow Light Tetra - Hemigrammus erythrozonus, the radiant orange Jewel Tetra - Hyphessobrycon callistus, the Flame Tetra - H. flammeus, and the red-tailed Pristella - Pristella maxillaris, all of which grow to less than two inches long.

Slightly larger Tetras include the Penguin Tetra - Thayeria obliqua and the closely related Hockey-stick Tetra - Th. boehlkei, both of which are easily recognized by the black lines originating in the lower half of their caudal (tail) fins and running forward, the shiny Diamond Tetra - Moenkhausia pittieri, and the beautiful, trident-tailed Emperor Tetra - N. palmeri. Finally, the only African Tetra frequently seen, the Congo Tetra - Phenacogrammus interruptus is a gorgeous fish which grows up to four inches long.