Fish Basics

Fish care is not as simple as putting a fish in a bowl of water and feeding it. Most fish require much more space than a typical fishbowl provides. The general rule of thumb is one gallon of water for every inch of adult fish. This is a good starting point, but it is only a starting point. Wide or tall fish (such as angelfish or silver dollar fish) need more space than sleek, narrow fish (such as danios or platies).

A proper tank should be large enough to accommodate your fish and equipped with a filter and heater. Water quality (levels of chlorine, ammonia, nitrite, and nitrite; pH; etc.) should be monitored regularly to be sure it is safe. Remember, just because your tap water is safe for you to drink does not mean it is safe for fish to breathe. Water conditioners remove chlorine and heavy metals from tap water to make it safe for fish. Even with a filter and water conditioner, you will need to routinely clean your fish tank.

Make sure your tank is “cycled.” This means establishing the good bacteria that will keep your fish healthy by converting ammonia from fish waste into nitrite and then into the harmless nitrate. There are there are three main ways to cycle a tank. The traditional way is simply to put fish in the tank and let them produce ammonia to kickstart the cycle. This method has its drawbacks, including increased maintenance requirements until the tank is fully established, as well as danger to the fish from unsafe water. A humane, fishless cycle is also possible with a little patience. Adding small amounts of ammonia to an empty tank daily will start the cycle in the same way as traditional cycling, but without endangering any fish. Finally, there are a few products on the market that can effectively cycle a tank in an instant. Basically, these products are the good bacteria. Whatever method you use, be sure to regularly test your water quality.

If you have multiple fish, be sure they are compatible tankmates. This means choosing fish that prefer similar water conditions, including temperature as well as freshwater or saltwater. Make sure the fish you choose are not likely to fight or eat each other. In addition, be sure that all of your fish have their nutritional needs met.



Professional fish keeper and editor-in-chief of Everything Fishkeeping magazine, David Thomas, has written the following article, Perfect Freshwater Fish for College Students, in collaboration with Pets4Life to set readers on the right track for picking the perfect underwater college companion.

Perfect Freshwater Fish For College Students

In many ways, fish are the perfect pet for a college student.

Their self-contained habitats make them easy to move, and they do not require the space and attention of a dog or a cat; they are also much more likely to be allowed in dorms and not cause issues with roommates.

However, fish can also be expensive and difficult to maintain, especially if the species is not chosen with care.

It is easy for a first-timer to get caught up in fancy saltwater fish with flashy colors, high price points, and complicated maintenance requirements that offer very little room for error.

Fortunately, there are many freshwater fish that make excellent starter fish, because of their combination of hardiness, friendliness, and cleanliness. The five listed here, however, may be the best of the bunch, and offer just about anyone an avenue into a thriving career as an amateur aquarist.


  1. Goldfish – The classics are usually the classics for a good reason, and it is not a coincidence that the goldfish has been the starter fish of choice for thousands if not millions of aquarists for decades. Their eponymous golden-orange hue is striking, and their small size (about four inches) means they only need about 20 gallons of water (at any temperature between 65 and 72 degrees) to thrive. Additionally, goldfish are both very hardy and remarkably calm, getting on well with other goldfish. Unlike the children who usually own them on TV shows, goldfish are not picky eaters and will be perfectly happy with any commercial fish food formulated for them, be it flakes, pellets, or even freeze dried.


  1. Guppy – Guppies are, unsurprisingly, small fish, usually between an inch and an inch and a half long; they thrive in as little as five gallons of water, kept between 72 and 79 degrees. While guppies have been bred into a variety of gorgeous color combinations, the flashier specimens tend to be more delicate and demanding, so beginners should trade down a few notches of sparkle for a simpler, more dependable fish. Guppies are even-tempered and will get along well with most similarly sized fish. Guppies are omnivorous, and in the wild, they devour mosquito larvae like potato chips, but in captivity they can thrive on almost any type of live, frozen, or dried food.


  1. Black Molly – While mollies come in a wide variety of colors and sizes, the black molly is the beginner’s best bet, because of their sociable nature and hardiness. Black mollies need at least a 10-gallon tank, as they are active fish that become aggressive when confined to too small a space. Anyone keeping mollies also needs to be careful about mixing the sexes, as mollies breed easily, and males will harass the females. Mollies also make good tankmates for other fish of similar size (about four inches). They are omnivorous and require a diverse diet heavy in plant fibers like algae and vegetables, and do best in water between 72 and 78 degrees.


  1. Zebra Danios – The zebra danios got its name from the beautiful stripes along its sides, which make it striking even at its small size (2.5 inches). They are an active and social fish, doing best in schools of at least five, though they have a tendency toward fin nipping with other species. The zebra danios does best in at least 10 gallons of water and can be happy in temperatures ranging from 64 to 74 degrees. They also prefer a diet heavy in live or frozen invertebrates and fresh veggies, though they are not particularly picky.


  1. Angelfish – While the saltwater varieties featured in Finding Nemo may be more famous, freshwater angelfish have the same spectacular fins and similarly striking colors – notably gold and silver – as their oceanic counterparts, with much easier maintenance to boot. Angelfish grow up to six inches long and can do well in 20-gallon tanks, so long as they are tall enough and densely planted, with water between 74 and 84 degrees. They are slightly territorial, especially when eating, and can be aggressive with other fish. The angelfish’s other best qualities are its hardiness and its broad diet; angelfish are more than happy to eat flaked, frozen, or live meals.


While choosing a first fish can feeling complicated and overwhelming, it is ultimately more similar to choosing a dog or a cat than it first appears. Things like the animals’ ideal climate, activity level, diet, and social exposure all need to be taken into account, but there are also the more fun factors, like appearance and markings.

Overall, narrowing the vast ocean down to a few practical options, like the ones listed here, then following your heart, is a reliable way to stock the first of what will hopefully be many aquariums to come.



More Information on Tanks and Water Maintenance

More Information about Fish Health and Nutrition

More Information about Choosing Compatible Tankmates