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.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.
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).
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.
Make sure you have all the proper equipment- filters, heaters (for tropical fish), water conditioner, test kit, etc.
Set up the tank and cycle it.
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.
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.
Test the water regularly. Make sure you have 0 ammonia, 0 nitrite, and under 40 nitrate.