Good Fish for Starting a Tropical Freshwater Aquarium

An illustration of good starter fish for an aquarium

Illustration: © The Spruce, 2018

Nothing is more exciting than adding new fish to a newly set up aquarium. However, the fish you choose will have a big impact on your tank's success or failure. Unfortunately, many new fish owners make the wrong choices, lose some or all of their fish right away, and give up on keeping fish.

The two biggest errors made when stocking a new aquarium are adding too many fish at a time and choosing the wrong species. Tip the scales in your favor by following these basic, but important, steps.

How Many Fish?

When you are considering the many beautiful fish at the pet shop, remember one word—moderation. In most cases, only two or three fish should be introduced to a tank initially. Once the nitrogen cycle is established and the tank is stable, additional fish can slowly be added. However, the same rule applies when adding the next round of fish. Moderation: you must add only a few at a time.

Factors in Choosing Fish

Fish owners tend to opt for fish with the most physical appeal. Pretty fish are sometimes acceptable beginner choices, but there are other more important factors to consider. A beginner fish should have these qualities:

  • Tolerates a variety of water conditions, particularly the conditions during startup
  • Accepts a variety of foods, and are easy to feed
  • Does not grow to be overly large
  • Not aggressive
  • Compatible with a variety of other fish (unless you're creating a single species tank)

Small schooling fish are generally good first fish, but take care to not add an entire school at once if the tank is new. If you want more than one species, do not start them all at the same time. Instead, build one school up before starting the next species.

Tetras, for instance, are a schooling fish to avoid in any new tank. Most are more sensitive to water conditions than other fish, and often will not survive the initial start-up cycle. It’s generally best to wait until the tank is mature before adding Tetras.

Good First Fish

Although the list seems small, there is quite a variety to choose from. Once your tank matures, you can branch out into other species of fish.

Wrong First Fish

If you are wondering why your favorite fish isn't on the "good first fish" list, here are some popular fish that you should not add to your new freshwater aquarium.

  • Catfish (some varieties): Many catfish are sensitive to the start-up cycle, or they grow too large to be good first fish. For example, the common Pleco is a hardy fish, but it grows to be very large. The Otocinclus is small but very sensitive to toxins that are usually present in a newly started tank.
  • Goldfish: Goldfish are cold-water fish that produce copious amounts of waste, which means that they require a larger tank all to themselves; and yet, the proverbial goldfish bowl is not an ideal home for the goldfish. If you want a goldfish, give it a nice roomy tank of just goldfish.
  • Live bearing fish: If you have children, you may be tempted to get live bearing fish. Because they require special conditions (most notably salt in the water) and are more susceptible to disease, they are not ideal first fish. If you do opt for live-bearing fish, choose one species only.

At the Fish Shop

Now that you've decided on the species of fish, there is one more important step–choosing healthy individuals. When you go to the shop, don't accept just any fish. Look them over carefully.

Avoid fish with wounds or nipped fins as they are likely to be more susceptible to disease. Check the eyes; cloudy eyes are a sign of poor water conditions and or disease. Also avoid fish with sunken bellies, as they have been chronically underfed and may be suffering from a disease.