4 Do’s and Don’ts When Buying Tropical Fish

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4 Do’s and Don’ts When Buying Tropical Fish

There are many factors to take into consideration when buying tropical fish. First-time buyers will need to decide which type of habitat they want to create in their aquarium. Freshwater, saltwater, and brackish species must be kept in separate tanks because of differing water chemistry needs. For best results, shoppers will want to select fish with compatible temperature requirements and similar behaviors. It’s also important to look for healthy fish with no visible signs of disease. Tank capacity is another concern when buying tropical fish.

It’s never a good idea to overcrowd a fish tank. For this reason, buyers are cautioned against adding too many fish to the tank at one time. Before introducing new tropical fish, steps should be taken to acclimate them to their new home. This will ensure a stress-free experience for the buyer and the fish. This guide outlines several do’s and don’ts to aid in the tropical fish buying process. Fish enthusiasts can find tropical fish for sale in pet shops and speciality aquarium stores. There are also many tropical fish available through Internet vendors and online auctions sites like eBay.

What to Do When Buying Tropical Fish

Before buying tropical fish, it’s advantageous to learn about their differing habitats and aquarium requirements. Exploring various species may help buyers decide which type they’d like to own. By researching vendors and breeders, people can feel confident their new fish will be happy and healthy.

1. Learn About Varying Tropical Fish Habitats

Before purchasing live tropical fish,, buyers must decide if they want freshwater, marine, or brackish tropical fish. These three types of tropical fish each live in separate aquatic ecosystems. Differing water condition requirements means they cannot all live together in the same aquarium. The aquarium ecosystem will need to be tailored to the particular species of fish it will house. The following descriptions will help first-time buyers choose which type of aquarium habitat to build.

Freshwater Tropical Fish

As the name suggests, freshwater tropical fish live in freshwater ecosystems around the world. There are thousands of freshwater fish species available for aquarium owners. First-time aquarium owners often choose freshwater fish because they are easier to maintain. The start-up equipment and supplies for a freshwater tank are less expensive than those required for a marine tank. Because so many freshwater species exist, it’s important to choose fish that can coexist together in a community tank.

Marine Tropical Fish

Marine tropical fish live in oceanic saltwater conditions. While giant marine aquariums full of colorful fish are certainly attractive, the upkeep costs can be prohibitive for many buyers. For this reason, it’s recommended that people start with a freshwater or brackish tank before moving up to a marine tank. There are two main types of marine aquariums: reef tanks and FOWLR tanks. FOWLR stands for "Fish Only With Live Rocks." These tanks only include fish, live rocks, and select invertebrates, while reef tanks also include live coral and edible invertebrates.

Reef tanks require a high level of planning and maintenance to duplicate this unique marine ecosystem. Fish-only tanks are another possibility, but they are not as realistic of an environment for marine fish to inhabit. There are close to 15,000 tropical marine fish available to buyers. Their environmental needs and dietary requirements vary considerably, so careful selection is essential.

Brackish Tropical Fish

Brackish tropical fish live in coastal areas where freshwater and saltwater meet. Their habitats include estuaries, swamps, and mangrove forests. Brackish water conditions are constantly in flux, depending on the tide, river output, and evaporation levels. Because of this, brackish fish are hardy aquarium dwellers. They adapt well to changing water conditions and tend to be easy to feed. Brackish aquarium setup is similar to that of freshwater tanks, but requires the addition of sea salt. Brackish fish prefer a salinity (also called specific gravity) of 1.015, which equates to two teaspoons of salt per gallon.

2. Compare Tropical Aquarium Water Chemistry Parameters

Freshwater, marine, and brackish tropical fish all require specific aquarium conditions to thrive. The following chart outlines general temperature and water chemistry guidelines for each type.

Type of Fish

Temperature (F)

pH Level

Specific Gravity


72 - 82 degrees

6.5 - 7.5



72 - 78 degrees

8.1 - 8.4

1.020 - 1.025


72 - 82 degrees

7.5 - 8.4

1.006 - 1.015

Buyers are urged to research the specific needs of the tropical fish species they are interested in purchasing. Specialized aquarium equipment aids owners in achieving the right conditions in their tank.

3. Explore Popular Species of Tropical Fish

With thousands of tropical fish species available, it can be hard to decide which type to buy. Before choosing a particular habitat to focus on, buyers should peruse all their options. Fancy goldfish,, which fall into the freshwater category, are among the most recognizable aquarium pets. The most famous species of freshwater Betta fish are known as Siamese Fighting Fish. Unlike other species, these hardy and highly territorial fish can survive in a small fish bowl, making them a popular choice for first-time buyers. Additional freshwater tropical species include Tetras, Cichlids, Koi, and Catfish..

The marine category encompasses a diverse array of attractive and intriguing species. Clownfish are a popular marine species known for their bright stripes and cheerful demeanor. Distinctive physical features make Seahorses and Lionfish an interesting addition to a marine aquarium. Brackish species may not be as vibrant as tropical marine fish, but they are easier to care for. Large Scats and Archerfish are popular for big brackish tanks. Smaller brackish species include the Black Molly and the Bumblebee Goby..

4. Purchase Tropical Fish from Reputable Vendors

Before buying tropical fish, it’s important to investigate the reputation of the store or breeder. Adding diseased fish to an aquarium can have devastating effects on the existing fish tank population. Buyers must exercise extreme caution if they decide to shop around for the best deal. When visiting a pet store or aquatic shop for the first time, start by looking for telltale signs of mishandling or neglect. Avoid stores with dead fish floating in their tanks.

Confirm that a quarantine tank is used to separate sick fish from the general population. While it can be tough to ascertain the health of fish purchased online, it’s not entirely impossible. First, research the reputation of the vendor or breeder. Then, determine if the pictures supplied are stock photos or images of the actual fish. Don’t be afraid to ask questions or request additional photos or video of the specific fish in question.

What Not to Do When Buying Tropical Fish

Newbie aquarists who fail to fully research tropical aquarium techniques might make potentially disastrous mistakes. When selecting tropical fish for an aquarium, compatibility and tank capacity are key. Never mix incompatible species, and don't add more than one or two fish to the tank at one time. Tropical fish with visible signs of disease should always be avoided. Additionally, to prevent injury or death, all fish should be properly acclimated before being added to their new home.

1. Don’t Choose Incompatible Tropical Fish Species

After choosing between freshwater, marine, and brackish tropical fish, buyers will need to select compatible tank mates. Fish from the same habitat aren’t necessarily compatible. Buyers will want to research various species to find out which ones can live happily together in the same tank. There are a number of factors that affect species compatibility. Fish often have special dietary requirements. Many also prefer specific environmental features.

Behavioral characteristics will need to be evaluated as well to ensure a healthy, balanced ecosystem. Some fish are loners and need plenty of personal space. Others like to swim in schools and would be unhappy alone. Certain species are prone to aggression, while others are shy and peaceful. For additional information, buyers may wish to consult tropical fish compatibility charts. These can be found on the Internet and in tropical fish aquarium guides..

2. Don’t Ignore Visible Signs of Disease

Buyers need to keep an eye out for unhealthy fish when browsing for potential additions to their tropical aquarium. The following advice will help people detect diseased and parasite-infested fish.

Look for Tropical Fish with a Healthy Appearance

After deciding which species to purchase, research normal coloration in order to assess health.

  •     Healthy fish are brightly colored with undamaged fins.
  •     Sickly fish will appear dull or pale in color.
  •     Patchy or dark coloration can be a sign of stress.
  •     Small white crystals or black nodules indicate parasitic infestation.

Avoid Tropical Fish With Signs of Poor Health

Unhealthy fish may have one or more of the following symptoms:

  •     Peeling scales
  •     Ulcers
  •     Boils
  •     Bulging Eyes
  •     Gill Discoloration
  •     Ragged Fins
  •     Lack of Appetite

3. Don’t Overcrowd the Aquarium

Stressed-out fish can quickly become sick fish, so tank overcrowding should be avoided. While it can be tempting to add a bunch of fish to a new aquarium, this approach can be troublesome. Instead, it’s better to only add a couple fish at one time. Fish should be given time to adjust to their new surroundings before more fish are introduced. To prevent overcrowding, buyers must evaluate the total capacity of their fish tank. This will help them create a feasible schedule for increasing the aquarium’s population.

The general rule of thumb for community tanks is one inch of fish for every gallon of water. Additional factors such as full-grown size and social behavior should also be taken into consideration. Certain fish, such as marine species or species that tend to be messy or territorial, may have specific space requirements. It’s up to buyers to carefully research the species they are interested in keeping. This will enable them to create a suitably sized aquarium habitat for their tropical fish.

4. Don’t Forget to Acclimate Tropical Fish to Their New Aquarium

Buyers should never dump tropical fish directly into their new aquarium.. This can cause unnecessary shock and stress, which can eventually lead to death. Don’t worry if the fish do not initially appear to be alive in their transport bag. Fish often become inactive during transport but will revive once properly acclimated to their new environment. For the safety of the fish, it’s recommended that buyers introduce them to the aquarium using a suitable method. There are three generally accepted ways of adding new fish to an aquarium. When using any of these methods, care must be taken to avoid contaminating the aquarium with transport water.

Floating Bag Method

The floating bag method involves placing the transport bag into the aquarium where the fish will reside. This is the most common method of aquarium fish introduction. The transport water is periodically replaced with tank water over the course of an hour. This allows the fish to slowly acclimate to tank conditions. After the acclimation process is complete, the fish can be netted and placed in the tank.

Bucket Method

The bucket method is very similar to the floating bag approach. The only difference is that the transport bag is placed in a clean bucket rather than in the tank. After that, the acclimation procedure is the same. Some people prefer the bucket method because it prevents transport water from entering the aquarium.

Drip Method

The drip method is the preferred way to acclimate marine fish and invertebrates. This method gives delicate fish plenty of time to acclimate to their new environment. Certain species are extremely sensitive to water chemistry. This means they’ll need extra time to acclimate to new conditions. To use the drip method, first place the transport bag in a clean bucket. Then, use rubber tubing to siphon and slowly drip aquarium water into the transport bag. Depending on the fish, drip acclimation can take up to three hours.

How to Buy Tropical Fish on eBay

You can find tropical fish in all shapes, sizes, and colors by searching eBay. To see all available tropical fish, type "live tropical fish&" into the search bar found on any eBay page. If this approach produces too many results,, consider using keywords that are more specific. If you’re interested in creating a saltwater habitat, try searching for "live marine fish&" or even a specific species like "live clownfish.." This should narrow down your search results considerably, making it easier to find the fish you want to buy. You might be interested in purchasing fish from a seller with an eBay Store.. If so, an advanced search can be used to limit your search parameters. To quickly compare tropical fish listings, add them to your Watch List.

How to Manage and Compare Potential eBay Purchases

The Watch List is a useful tool for keeping track of eBay item listings. While browsing for tropical fish, add your favorites to your Watch List. This way, you can easily return to listings for fish you may want to buy. You can also quickly compare items you are watching. To keep track of fish compatibility and other important information, use the "add a note&" feature.


There is much to consider when selecting tropical fish for an aquarium. For starters, buyers need to determine which type of fish can survive in their aquarium. Freshwater, brackish, and marine tropical fish all live in differing habitats. They need to be housed in tanks that match the conditions of their natural environment. When buying tropical fish, special emphasis must be placed on compatibility. In-depth research about tropical species will ensure that fish can coexist peacefully in their aquarium habitat. It’s also essential that buyers look for healthy fish that won’t infect other tank dwellers with disease.

Buyers might be eager to purchase a number of tropical fish, but they should exercise control in their purchases. Adding too many fish to a tank all at once can have dire effects on the water quality and health of the fish. Instead, it’s better to slowly increase tank population without exceeding total capacity. Additionally, it’s important to learn the proper procedure for adding new fish to an aquarium. This will help fish adapt to their new environment without becoming stressed or shocked. Buyers looking for live tropical fish can start by searching the eBay stores and auction listings.

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