Buying new fish for your aquarium is exciting! Whether you’re new to the hobby or a seasoned veteran looking for something new and interesting to add to your aquarium, going to the fish store is just plain fun. There are so many fish to choose from you might have trouble deciding what to buy, and you could find yourself wanting them all! But before making any livestock purchase, there are some important questions you should ask to make sure you’re making the right decisions for yourself and the fish.
Questions to Ask Before You Buy New Pet Fish
1. How big will the fish get? Many of the pet fish species you see in the store aren’t fully grown. Some may only get a little bigger, while others may double, triple or more in size. Always make sure the fish you intend to buy will fit comfortably in your aquarium when they reach adult size.
2. What does the pet fish eat? While most tropical fish do just fine on a diet of flake, pellet or frozen foods, some species are specialized feeders that may require live food or customized feeding methods. Some pet fish may grow up to eat the rest of the fish in your tank, while others may be herbivores that will decimate a beautifully planted aquarium. Before purchasing any new aquarium fish, make sure you have the means and dedication to properly feed it and that it won’t devour the rest of your aquarium’s inhabitants or plants.
3. Is the fish species peaceful or aggressive? If you have peaceful fish, you don’t want an aggressive fish that spends its day chasing everyone else around, stressing them. On the other hand, if you have rambunctious fish, you wouldn’t want to add a shy fish that will be constantly harassed and running for its life. While some fish may not kill their tankmates outright, being chased, nipped and kept from feeding will eventually take its toll on the victim, resulting in increased susceptibility to disease or even death. Click here to learn more about fish personalities.
4. Is the fish territorial? There’s a difference between being aggressive and being territorial, although some fish can be both. Territorial fish will often tolerate other tank inhabitants as long as they have enough space and structure to define their territorial boundaries. They may chase other fish away if they come too close, but they will otherwise leave them alone. Territorial fish often do not tolerate other members of their species, so it’s best to just buy one.
5. Will it get along with my fish? Keep a list of the fish you have in your aquarium. If you’ve forgotten or aren’t sure what kinds of fish you have, take pictures to show store staff so they can help you make the right choices. Learn more about fish compatibility in our helpful article Fish Compatibility: How to Build a Peaceful Community Fish Tank
6. Does it need special water parameters or temperature? While most tropical fish sold today are raised in captivity and tolerate a certain range of water chemistry parameters, some are still collected in the wild and may need a specific pH, alkalinity or temperature to thrive. Always research the type of fish you intend to buy or ask if they need special conditions.
7. How many fish should I buy? Some fish are solitary and as adults they do not tolerate others of their own kind or closely related species: betta fish, certain gouramis, redtail and rainbow sharks, and some cichlids are good examples. Schooling fish (tetras, barbs, danios, rasboras), on the other hand, do best in groups of 6 or more and may hide or become stressed if kept individually or in smaller groups. Livebearing fish (guppies, mollies, platies and swordtails) do best in a ratio of two females to one male as the males tend to be relentless in their efforts to mate.
8. How long do pet fish live? Small fish like tetras, barbs and danios should live at least 5 years, if not longer, while medium sized fish such as angelfish and goldfish often live 10 to 15 years. Larger cichlids, clown loaches, and many plecostomus and catfish species can live 20 years or more, while koi are known to live even longer. Plan accordingly.
9. How long has the fish been in the store? Never buy a fish that has just arrived in the store. Shipping stress temporarily lowers a fish’s resistance and increases its susceptibility to disease. Moving it again without giving it a few days to stabilize will only compound the problem. This is especially true of wild caught or delicate species.
10. What part of the aquarium will it occupy? Many fish spend their time at specific levels in the water column, and it’s important both visually and in terms of compatibility to have equal proportions of surface, mid-water and bottom dwellers. Crowding fish in any layer may result in conflict and stress to some of them.
11. What type of habitat does it need? In nature, fish occupy specific habitats such as open water, plant beds, rock structure or fallen trees. Always research fish before you purchase them and make sure you have the proper habitat in your fish tank.
Asking key questions and making sure you have the right conditions for fish before purchasing them will ensure they live long and happy lives and result in many years of enjoyment with your aquarium