Choosing fish for your aquarium can be a very overwhelming task. It is very hard to sort through the almost unlimited options and come up with a list of fish that will all get along with each other, not outgrow the tank, and can all be kept in the same conditions. Their maximum size, behavior, natural water parameters, and more all have to be taken in to consideration. The problem is that it can be hard to find an accurate source for all of this information. It seems that as soon you decide what you want when you go to fish shop to see which ones they have you find three more types you want but didn’t have on your list.
The best source for accurate information about the maximum size, natural temperature range, etc. is fishbase.org because it is used and maintained by scientists. Most aquarium fish websites are made by and used only by hobbyists. Unfortunately this means that most simply repeat what every other website says without any backup information, or they all conflict with each other and you have no idea of knowing which is accurate. If you always check fishbase.org you can be confident that almost all the information you find will be very accurate.
One of the best things you can do is write down all the fish you see that you like. Then go through that list and determine all the species that will grow too large, become too aggressive, or need different water parameters from most of the fish on your list (or your tap water water). You can also take this list in to your local fish shop and have them help you determine which fish need to be eliminated from your list. Also keep in mind that many fish you may see online or in a book may be extremely rare or impossible to find in the hobby, or simply out of your price range.
Fish That Grow Too Large for Aquariums:
One major problem is that the large pet stores sell a lot of fish that should not be in the hobby. The best example of this is the red belly pacu. They can grow to over three feet and are a very heavy fish. They can also live for forty years or more. These fish can be found in almost any large chain pet shop at 1-3″ and sell for under $10. They are a beautiful and very enjoyable fish. Unfortunately they are one of the fastest growing fish species and get very large very quickly (18″ within 1-2 years). They can hit one foot within six months. In nature they mimic red belly piranhas until they are larger than piranhas ever get, at which time they change colors to gray and black (commonly mistakenly called black pacu). However, pacus are far from the only fish that shouldn’t be easily available but can be found in almost any pet shop. Common plecos can grow to over two feet and once they hit 6-8″ or so are not good for algae control and simply create huge strings of poop that can be over two feet long. They can also grab on to the sides of fish and do some severe damage. Many other species of plecos have one or more of these problems as well. The common algae eater, also known as the Chinese algae eater, also grow larger than most community tanks can handle. They also can get aggressive and chase down fish and suck on them. Red tail sharks and rainbow sharks can become nippy and even aggressive when fill grown, a problem in the community tanks they are usually recommended for. Although they are not common in most large chain pet stores, there are many other species that should not be in the hobby except for the exceptionally rare aquarist. These species include but are not limited to: arowanas (all species), South American redtail catfish (can grow to over four feet), tiger shovelnose catfish (can grow to around three feet), almost any freshwater stingray (even the smallest species need tanks that are at least 24″ wide and at least six feet long, some recommend much larger as a minimum), and many species of bichir (Polypterus spp., some of which can reach two to three feet long).
Modified Body Shapes and Coloration:
Because of mankind’s ability to alter domesticated animals we have managed to create some very unnatural body shapes, coloration, and finnage. There are many species of aquarium fish that are available in long-finned varieties, albino and other color morphs, and even ‘balloon’ or round-bodied varities. This creates more options for the aquarist, but some of these changes can have some pretty severe side effects. The most common problem is the ‘ballon’ body which basically compresses all the internal organs of the fish and forces them to have an unnatural arrangement. This can cause swim bladder and digestive system problems. This is very common in fancy goldfish. This can also be an issue with balloon mollies and even ballon rams.
To make it even more complicated we have been able create very unnatural hybrids, such as parrot cichlids. Parrot cichlids have a very round body and an altered mouth shape (some can’t even close their mouth). Making it even worse is that the parrot cichlid is one of the most commonly dyed and tattooed fish.
Fish that are Dyed, Injected, and Tattooed:
Many species of fish are dyed, injected with pigment, and even tattooed with hearts and other designs. This is an absolutely horrible process for fish. Shipping and selling fish has enough risks and be stressful already, stabbling needles into them and dying them is simply unnecessary harm. The most common species are parrot cichlids (their natural coloration is as light as yellow or as dark as a red-orange, sometimes with black blotches, any other colors are dyed), glass tetras (injected with lines of fluorescent dye, the injection site is extremely prone to ich infections, they are commonly called painted glass fish or painted glass tetra), mollies (usually tattooed so they are very obvious), and even redtail loaches (dyed various colors, the natural coloration is a light blue with red tail), fruit tetras (‘strawberry’ and ‘blueberry’ varieties as well as other colors), and many more. With so many fish that are naturally so colorful there is simply no reason to support such a horrible practice. I suggest you do not buy any fish from a store that sells any fish that are dyed, injected, or tattooed. For more information please visit DeathbyDying.Org.
I do want to specify that Glofish™ are not dyed, injected, or tattooed. They are zebra danios that have been genetically modified. What this means is that the original fish had a gene for a fluorescent protein added to their genome and now this coloration breeds true from one generation to the next. There are currently five color varieties (green, red, orange, blue, and purple) as well as the recently released Glofish™ tetra (green). All six varieties are hardy, brightly colored, and a great addition to a community aquarium.
The article Stocking an Aquarium has a lot of information about properly stocking an aquarium and should be consulted before making any final decisions.
Where to Buy From:
Selecting the individual fish to add to your aquarium can be even more challenging than figuring out your stocking plan. You need to find a store that stocks a variety of healthy fish for you to choose from.
The ideal fish store is a small local business. There are enough big companies in this country that may offer slightly lower prices, but the small local business is more likely to have higher quality livestock and dry goods and better knowledge. Stop in once or twice and ask questions. They should be happy to answer any you may have (but don’t hold it against them if you go on a busy Saturday and you don’t get that much one on one time with anyone working there). The best shops will go to a wholesaler and hand pick every fish that comes in to the store. Many will also buy from local private breeders, but their selection for this can be extremely limited to no fault of their own. Do not be discouraged if they use central filtration. Many people may tell you that individually filtered tanks is better because sick fish in one tank can’t infect the fish in other tanks, but I have worked with both types of filtration and have found central filtration to be the much better option. A good central filtration system should have a UV sterilizer so that the water from one tank cannot get to another tank without going through the UV sterilizer, which can kill pathogens. Central filtration means that the whole system is much larger and therefore much more stable. This means less stress for the fish and less stress means healthier fish. Ask them what food they feed and why. They should feed a high quality food. This may cost them a little more, but the better nutrition will mean the fish will be healthier. Watch the employees catch fish. Do they use one net and chase the fish around erratically or do they use two and calmly catch the fish? There is definitely a learning curve to properly catching fish and one employee not being good at it doesn’t mean the fish shop is a bad option, just that you may want to ask a different employee to catch your fish.