Choosing PetSmart fish responsibly starts before you reach the checkout: first decide what kind of aquarium you can maintain, then select fish whose adult size, social needs and water requirements fit it. A fish that looks small in a store tank may need a group, warmer water or more swimming space at home. Prepare and cycle the aquarium before bringing fish back, and budget for equipment and routine care as well as the animal itself. PetSmart’s selection and in-store information can vary, so confirm the exact species and its requirements with the tank label, an associate and a reliable care reference.
Start with the fish’s full identity, not just a broad label such as “tetra” or “catfish.” Related species can differ in adult size, preferred water conditions and behaviour. Ask for the common and, where available, scientific name. Then find out how large the fish gets, whether it needs companions of its own species, what it eats and whether it is compatible with the fish you already keep.
Next, compare those needs with the aquarium you have or can maintain. Consider its capacity, filter, heater, water conditions and available swimming space. A fish that needs a group can’t be planned as a single addition; the whole group and its impact on the aquarium’s biological filter matter. Don’t rely on a general “inches of fish per gallon” rule, since it doesn’t account for body shape, activity, social behaviour or filtration.
Be realistic about time and ongoing costs, too. Fish need consistent feeding, water testing, aquarium maintenance and observation. Equipment may need replacement, and illness or a malfunctioning heater or filter can create unexpected expenses. If you can’t keep up with the required maintenance or provide a suitable aquarium, wait rather than choosing a fish that doesn’t fit your circumstances.
The options below are examples of familiar freshwater aquarium fish, not a guarantee of what a particular PetSmart store stocks. Care varies by species, so confirm the needs of the exact fish you’re considering before buying.
| Fish | Social needs | Habitat considerations | Think twice if… |
|---|---|---|---|
| Betta | Often kept singly; compatibility with tankmates depends on the individual fish and the other species. | Plan for a filtered, heated aquarium with room to swim. Avoid treating a small bowl as a suitable long-term home. | You want to add tankmates without researching their needs and the risks of aggression or fin damage. |
| Guppy | Social fish; males and females kept together can produce fry. | Check that water conditions suit the fish and plan for the possibility of a growing population. | You don’t have space or a plan for offspring, or you haven’t checked how a proposed group may interact. |
| Tetra | Many types are schooling fish, but appropriate group size and behaviour vary by species. | Identify the exact tetra and check its adult size, water requirements and compatibility with tankmates. | You plan to keep one or two without confirming whether the species needs a group. |
| Goldfish | Social needs and compatibility depend on type and tank setup. | They grow and produce substantial waste, so plan for a spacious aquarium and capable filtration. | You have a bowl or a small aquarium, or you’re planning to mix them with tropical fish without checking requirements. |
| Corydoras | Many are best kept with others of their own species; confirm the needs of the specific type. | Provide suitable bottom space and food that reaches them. They are not a replacement for aquarium cleaning. | You expect them to survive on leftover food or keep the tank clean by themselves. |
The main lesson is that a fish’s appearance or store-tank size doesn’t tell you whether it suits your home. For example, a small goldfish still needs a plan for its growth and waste, while a schooling species may need several companions rather than a solitary place in a community tank. A betta may be a better fit for someone seeking a single-fish setup, but its temperature, filtration and space requirements still need to be met.
Compatibility also involves more than whether fish are described as peaceful. Check whether their temperature and water preferences overlap, whether they may nip fins or eat smaller tankmates, and whether they use different areas of the aquarium. If one fish’s needs conflict with another’s, choose a different combination rather than trying to compromise the habitat.
Setting up a tank in advance gives you time to check that the equipment works and the water is suitable. A clean-looking aquarium isn’t necessarily ready: its biological filter needs beneficial bacteria that process fish waste. Adding fish before that system is established can expose them to harmful ammonia and nitrite.
Keep a test kit and water conditioner on hand before the first fish arrives. If you already have an aquarium, check its current water and stocking before adding new animals. A filter’s presence alone doesn’t show that the tank can support more fish; its biological capacity depends on the system and its existing occupants.
The purchase price is only one part of the cost of PetSmart fish. Before choosing a species, account for the equipment and supplies needed to keep it well, along with the time and money required for routine care.
Costs depend on the species and setup, so compare the requirements of the complete aquarium rather than looking for a single universal estimate. A more demanding fish may require a larger tank, stronger filtration or more specialised care. If the setup exceeds what you can sustain, choose a fish with compatible needs—or postpone the purchase.
Once your aquarium is ready, take time to observe the fish before selecting one. Ask a PetSmart associate for the exact species name and care information, and compare that information with a reliable aquarium-care reference. Store labels and general advice can help you identify a fish, but they may not answer every question about adult size, group needs or compatibility.
A fish that hides briefly or behaves differently from a tankmate isn’t necessarily sick, and a short store visit can’t confirm its overall health. Treat visible warning signs as a reason to ask questions or wait, not as a diagnosis. If you already keep fish at home, consider using a separate, properly equipped quarantine aquarium for newcomers; it should be monitored and maintained like an aquarium, not improvised as a jar.
Transport and introduction can be stressful, so make the journey direct and follow species-appropriate acclimation advice. On arrival, avoid pouring store water into your aquarium. Differences between the bag water and tank water can also matter, so ask for a suitable acclimation method and don’t leave a newly opened transport bag sitting for a prolonged period.
After release, keep the aquarium calm and watch the fish without repeatedly disturbing it. Offer food in small amounts once it has settled, and remove anything uneaten. If you add more fish later, do so gradually and monitor water quality; adding several animals at once can place a sudden load on the filter.
Good fish care is mostly consistent observation and maintenance. Feed an appropriate diet in measured amounts rather than assuming more food means better care. Uneaten food adds waste, and different fish may feed at different levels of the aquarium, so make sure each animal can get suitable food.
Follow a routine for testing water and performing partial water changes, adjusting it to the aquarium’s readings, stocking and species. Watch for changes in appetite, breathing, swimming, colour or interaction with tankmates. A change may point to a water-quality problem or illness, so test the water and seek knowledgeable help rather than adding medication at random. Medication can affect fish and aquarium bacteria, and not every problem has the same cause.
Include aquarium maintenance in your regular schedule, even when the water looks clear. Clean equipment as directed, check that the heater and filter are operating, and keep replacement supplies available. Consistency makes it easier to notice changes early and reduces the chance that an avoidable equipment or water-quality problem becomes urgent.
It’s better to wait until the aquarium is fully set up and its biological filter is established. A clear, treated tank isn’t automatically ready for fish; test the water and confirm that ammonia and nitrite are not detectable before buying.
There’s no single best choice for every beginner. A suitable fish is one whose group, space, temperature and water-quality needs match the aquarium and care routine you can maintain. Research the exact species rather than relying on a broad “beginner fish” label.
That depends on the individual betta, the proposed tankmates and the aquarium setup; compatibility isn’t guaranteed. Research the needs and behaviour of every species, and don’t add tankmates if you can’t provide a suitable separate home should the combination fail.
There’s no reliable universal number based only on tank volume or fish length. Consider adult size, group requirements, activity, compatibility and the filter’s capacity, then add fish gradually while monitoring water quality.
Pause and ask store staff about the tank before making a decision. A dead fish doesn’t explain the cause or establish the health of every other fish, so avoid guessing and consider returning another time if you still have concerns.
The best PetSmart fish for your home is one whose adult size, social needs and water requirements match an aquarium you can maintain over time. Confirm the exact species, prepare and cycle its habitat, and budget for routine care before bringing it home. If any part of that plan doesn’t fit, waiting is the more responsible choice.
