How to Take Care of Your Fish (Tanks)

Fish come in all different shapes and sizes. You name it: spikes, tails. Fish are cool. But how do you look after them? All those water chemicals, live food, and business about putting two fish in the same tank sounds scary. However, don't sweat it... just read this guide! It contains all the information you need on taking care of those first fins.


  1. Image titled Take Care of Your Fish (Tanks) Step 1
    Decide whether you want Tropical or Coldwater fish. Coldwater fish include goldfish and minnows. There are many types of tropical fish, from angelfish to corydoras catfish. Coldwater fish are usually a little more hardy, and will survive those first few mistakes, but they need more room.
    • Start off with inexpensive fish, even if you can afford expensive ones. Inexpensive ones are inexpensive because they are very successful in their natural environments or so comfortable in captivity that they even breed regularly and, in either case, do not die easily on their way to and in pet stores.
    • Do not start out with saltwater fish. They require techniques and understanding that are much more complex. Plus, the water you'll have to work with and that may leak is messy, slowly corrosive to metal, and conductive. If you believe you want a saltwater tank, get a medium sized tropical fish tank with some plants and see if you can keep that in perfect order first for a year or so.
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    Decide what kind and how many fish you want.
    • Research before putting species together. Some fish are compatible, others aren't. One might speculate that fish would enjoy some activity in their lives, so don't get just one. (The fish need not be the same species; for some territorial fish, it is best that it isn't. An armored catfish can be a good "companion" for such a beast.)
    • Make sure you can provide any specialized care the fish need. For example, different fish need different foods, and some fish require more frequent maintenance than others. Owning fish is a big responsibility.
    • Some fish are perfectly happy with flakes and can be fed with an automatic feeder, which makes it possible to leave the tank unattended for a week or two (assuming the fish are small so the water doesn't need very frequent changing).
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    Get an appropriately sized tank. Look up the minimum tank size for each fish.
    • For goldfish, buy a tank with 20 gallons (75.7 L) for the first goldfish, and 10 gallons (37.9 L) for each additional goldfish.
    • For freshwater fish, forget about one gallon per inch of adult fish. would you keep a 50 inch (127.0 cm) fish in a 50 gallon (189.3 L) tank?
    • Bigger is better. Even if the fish looks small, it will thrive in a bigger tank.
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    Make sure you have all the proper equipment- filters, heaters (for tropical fish), water conditioner, test kit, etc.
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    Set up the tank and cycle it.
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    Put your fish in. Only add a few fish to start with, and slowly build up the population. Adding too many fish at once can overload your filtration system.
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    Perform partial water changes weekly. 20-30% is a good amount. To do a water change, get a gravel vacuum and siphon out any waste in the substrate. This will pull out water at the same time. Replace the water with water from your tap, but remember to treat it with a water conditioner.
  8. Image titled Take Care of Your Fish (Tanks) Step 8
    Test the water regularly. Make sure you have 0 ammonia, 0 nitrite, and under 40 nitrate.
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    Feed your fish two or three times a day.
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    Monitor your fish. While they eat, sit and observe them. Check for anything strange: changing color, falling off fins, damaged tails, etc. Also, make sure all your fish are getting along.
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    Try not to stress out your fish. This includes putting your hand in the tank when you don't need to, touching them, or jumping near the tank. Try not to make too much unnecessary noise.


  • Don't feed it too much or it will die. Give it the amount that you are supposed to feed it. Ask the people of the pet store if you are unsure.
  • Try to remember to clean your tank once a week to keep your fish healthy and your tank looking presentable.
  • Never jump near your tank or try to touch your fish as it will stress them and they might not eat for a few days.
  • You might want to check the water temperature before you put the fish in the tank.
  • Make sure you match the fish appropriately, so they will not fight or kill each other.
  • Only put 1 or 2 fish in the tank when you start.
  • Always remove stray algae floating around the tank as it may cause the fish tank to be cloudy.
  • Don't change out the filter cartridge. The filter is where most of the beneficial bacteria lives and replacing the cartridge creates a buildup of ammonia that can kill your tank. Only replace it when its falling apart, even then, keep a small piece in the tank until the new filter cartridge has developed beneficial bacteria, about a month.
  • Don't use saltwater for freshwater fish and vice versa.
  • Buy a liquid test kit, as opposed to the strips. Liquid kits are much more precise and less likely to make error than kits that use strips.
  • Don't put to much or to little decorations or your fish may become stressed out.
  • ALWAYS research the different species that you are going to be putting into your tank. The people at the pet store are sometimes not very knowledgeable. Instead, go online and learn things from people who know a lot about fish.
  • Live plants can improve water quality and make your tank look more natural.


  • Air fresheners can also be highly toxic.
  • If your tank holds less than 2.5 gallons (9.5 L), do not use a heater. If you do, you'll be slowly boiling your fish. Get a larger tank, so you can have room for all your fish.
  • Don't leave out the changing water bit. If you don't do it, toxins build up, making your tank unhealthy and promoting nuisance algae growth.
  • Don't mix clownfish or Siamese fighting fish (betta) with other species.
  • Never clean anything which will be associated with your tank with soap, detergent, or washing powder. These will immediately kill off fish.

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Categories: Fish