Image credit: Amsk

Even though the Goldfish is commonly sold as the first fish, they are not the best choice for beginners

How many fish can I keep in my aquarium?

The most common rule for the number of fish in a tank is one inch (2,5 cm) of fish per gallon (3,7 to 4,5 litres) of water. This rule can be used but you should always remember it's rather inaccurate. All fish have different size and shape, and these factors should be taken into account as well. Housing ten inches slender shaped zebras in a ten-gallon tank is not the same as housing there ten inches of full-bodied goldfish. Another factor is the surface area of the water. The larger it is, the better oxygen exchange the water has. It means that more fish can be placed in a tank. A tall thin aquarium may hold the same amount of water as a short and wide one, but the surface areas will be very different, and it should impact the number of fish directly. Lastly, the more fish you place in a tank, the more time you will have to spend for its cleaning and keeping all the necessary parameters at due level. Besides, the risk of various fish diseases gets higher if the tank contains too many fish.

Why do aquarium stores have so many fish in their tanks?

Aquarium stores have special staff that clean the tanks and change the water daily.

How often and how much should I feed my fish?

The frequency of feeding depends on the type of fish. Most species do well with one feeding per day, although some owners prefer to feed twice. Whatever way you choose, the main rule is that the portions are small. Aquarium fish can hardly die from hunger (except those that eat algas), while overfeeding can cause many more problems. It is, actually, the most common mistake beginner aquarists make. If you notice that food is left uneaten within 5 minutes, reduce next portion. When in doubt, underfeed! You can always give another small portion if necessary. Remove all uneaten food with a siphon or net.

My fish seem very hungry every time I feed them. Is that normal?

Yes, it's normal and it's good because it means your fish are healthy. When they are inactive and don't want to eat, it is a sign of possible disease or bad conditions in the tank.

What lightning is necessary for my aquarium?

The lightning depends on what you are going to keep in your aquarium. If you want to keep live plants in there, you will need bright lightning that will be on for at least 8 hours a day. If the tank won't contain live plants, the lightning will have to be on for about 4-5 hours a day. The more lightning an aquarium has, the faster various algas grow, the more often you will have to clean the tank and its accessories.

What about fish diseases?

To avoid fish diseases, you have to follow three simple rules:
1) provide your fish with healthy water at the correct temperature,
2) eliminate all stressful factors such as temperature changes, insufficient filtration, cloudy water, bullies and nippers, excessive organics, and low oxygen level,
2) feed the right food and do not overfeed (elephant noses don't like flake food),
3) do not put unhealthy fish in the tank and quarantine new fish.
If you notice a sick fish in the aquarium, immediately take it out and put in a separate "quarantine" tank. After that, you can start handling the disease. For freshwater fish, the most common medication is table salt. Per every 5 litres of water, use 1 table spoon for prophylaxis, and 2 table spoons for treatment. For example, to remove leeches, it should be enough to bathe the fish in such a solution for about 15 mins. Do not use salt with scaleless fish such as Cordydoras and Tetras because they are very sensitive to it. Instead, use special medications you can use in an aquarium store.

What fish are best for a beginner?

There are many opinions about this. Some think that beginners had better get viviparous fish such as Green Swordtails, Guppies, Mollies, etc. But this is a mistake in a way because these fish don't live long and are often fished out of natural reservoirs, which means you can easily bring parasites and diseases to your tank. It is better if beginners get robust active fish easy to take care of.
Best fish for complete beginners: Danios, Rasboras, Barbs, Corydoras Catfish, Rainbowfish
Good fish for beginners with some experience: Loaches, Dwarf Plecos, Tetras, Cichlids, Anabantids, Guppies, Mollies, Platies
Bad fish for beginners: Piranhas, Knife Fishes, Hatchet and Pencil Fishes, Elephant Nose and Baby Whale, Sharks, Glass Catfish, Salt Water Fish
Even though the Goldfish is commonly sold as the first fish, they are not the best choice for beginners because are often sold full of diseases and parasites. It may kill them and other fish in the tank they are placed with.