What is the difference between a "beginner tank" and a beginner’s tank? A beginner’s tank is simply one owned by a beginner. But the term "beginner tank" also implies a certain stigma…for better or worse it is set up in the typical way that beginners set up their first tank. The typical way a beginner, in Calgary in the year 2000, sets up a tank is this: the tank is about 40-liters in capacity, has an undergravel filter, a semi-submersible heater, an inexpensive single tube (or incandescent bulb) light/hood, a small power filter, and plastic plants. It is usually stocked with a few live bearers, a few tetras or barbs, and a single Corydoras catfish.

However, it is not necessary for a beginner to start out that way. It is possible (however unlikely) that the beginner was introduced to the hobby by an advanced aquarist who introduced him to living plants at the same time. Such a beginner could set up a fairly advanced looking tank the very first time out…complete with living plants and the more comfortable surroundings, more stable water conditions, and increased oxygen supply that plants give to fish.

But both planted and unplanted tanks are likely to suffer from the same beginner’s mistakes: over feeding, under feeding, over crowding; incompatible species mixes, insufficient climatization, temperature fluctuations, and intermittent neglect. It’s just that the consequences of this aren’t as bad if the tank has plants in it.

So what fish are good beginner’s fish? Actually, most of them, so a better question would be "what fish aren’t". And an even better question would be "which fish, among those fish a beginner is likely to buy, aren’t". A stingray is not a good beginner’s fish, but at $140 a pop a beginner isn’t likely to buy one anyway. However, there are several fishes that are commonly sold to beginners that in my opinion should not be.

First of these is the fancy guppy. On the face of it, the guppy should be a perfect beginner’s fish: easy to breed, small, active, non-aggressive. And wild type guppies are. But fancy guppies are very often so inbred that their genetic strength is pretty much down the toilet. Fancy guppies have very short reproductive lives (often being "old" by nine months of age), they swim only with labor, and have lowered fecundity. They also are prone to "death without known causes". But wild-type guppies are often no better, as the ones available nowadays are relegated to the "feeder" tank, sold for 10¢ a piece, and subject to neglect. So if the wild-type guppies are likely to be neglected, and the fancy guppies are likely to be genetic trash, should the beginner still have guppies? Yes, but I would definitely not buy them from a pet store… go to a guppy breeder. Another option is buy "Endler’s livebearers". These look a lot like guppies, but they are almost certainly a separate species. They are endangered in the wild and being maintained in the aquarium as a genetically sound fish. And of course they tend to be very well cared for.

Another fish for the beginner to avoid is the molly, of all types. Many domestic strains suffer from the same genetic defects as fancy guppies (there is even a misshapen "balloon" molly available, shudder). And wild mollies are surprisingly expensive. Also quite surprising is that mollies are quite sensitive to changes in temperature… surprising since they live quite happily in central Florida where winter temperatures can easily drop below 15C. And mollies like some salt in the water, which is often not good for their tank mates. It is best to leave mollies to the advanced hobbyist willing to provide them with their own quarters.

Swordtails might not be such a great idea either. A much better idea than mollies, perhaps, but I would still only recommend them with some trepidation. There are several types of high-fin swordtails available that are simply genetic garbage. These fish are even unable to breed at all without artificial insemination. But even setting aside these inbred-to-oblivion fish (which I can’t imagine anybody wanting), the typical swordtail can be a fairly aggressive fish. This doesn’t seem to get mentioned much, but swordtails can be very bossy. They really need more elbow room than the typical beginner’s tank will likely provide.

Another fish that I would not recommend to the beginner is the neon tetra. Neon tetras were historically considered to be very difficult fish. Most certainly not for the beginner. But then Southeast Asian fish breeders learned the secrets of neon breeding and started mass-producing an aquarium-strain neon. They bred a fish that looked like the wild neon but was much more adaptable to the aquarium environment. The result was a fish that was inexpensive, colorful, peaceful, and hardy – the perfect beginner’s fish. So why don’t I recommend them? Well, neons don’t seem to be very hardy anymore. I am not sure why. Maybe its because their price has dropped so low that they are no longer given adequate treatment during shipping ("who cares if they die, it would be cheaper to just order another batch than package these properly"). Or maybe the aquarium neon has now become so inbred that it’s suffering from its own genetic deficiencies. Maybe they are selling poisoned fish so that the customer will come back and buy more. I don’t know. But I do know that a lot of neons seem to die within a week of being purchased.

Another fish often sold to the beginner that should not be is the Chinese algae eater. Hell, these fish shouldn’t be sold to anybody. They are also mass-produced in Southeast Asia nowadays and so are sold as inexpensive algae eaters. But they really don’t eat all that much algae. Instead, they seem to prefer to suck the slime off of other fish. And the older they get, the less algae they eat, and the more slime they suck. They are also prone to extremely hyperactive behavior (try catching one with a net sometime) and sudden death (from heart attack?). In a suitably large tank with lots of cover they might settle down to a long life, but after they reach 10cm or so in length they will mercilessly harass their tank mates. I once owned an enormous 25cm monster that was probably the most annoying fish I’ve ever met.

Dwarf gouramis. There has been an explosion of new color strains of dwarf gouramis around lately, again thanks to Southeast Asian breeders. And so nowadays pet stores will have several tanks of colorful dwarf gouramis at low prices. But I would not recommend them to the beginner. They are very shy fish that really can’t compete with the barbs and tetras the beginner will likely put them in with. Give them their own well-planted tank in a quiet corner and they are wonderful fish. In a tank without much cover (but with lots of tiger barbs) they will be thin, pale, and unhappy.

The most common fish purchased by the beginner is the goldfish. There are two things that could be wrong with this. First of all, many beginners try to mix goldfish and tropical fish. This is never a good idea, and goldfish should not be kept at temperatures above room temperature. And the second problem is that practically all beginners fail to give their goldfish enough room. Adult goldfish need at least 100 liters of water per fish. Not even one can be housed in the typical beginner’s sized tank for the long term. But for the beginner who keeps goldfish at a suitable temperature in a suitably large tank or pond, goldfish are very good fish indeed. Just stay away from those grossly malformed varieties that can’t even swim properly anymore. Like all fish that have resulted from such misguided breeding programs, their genetic soundness is absolutely miserable.