Q: “How Many Fish Can I Keep?”
A: "As Many As You Can Stuff Into Your Aquarium"

The Problem With "How Many?"

The above answer isn't very helpful is it? Most people have enough common sense to know that literally stuffing their aquariums with fish would result in dead fish, but they ask the question anyway. The question is missing some very important qualifiers, like the desired lifespan of the fish, yet new aquarists forget to stop and think about what they are actually saying sometimes. Subsequently, many new aquarists wind up in an interesting predicament: multiple "right" answers. Depending on who is asked, the answer will vary wildly because the question is missing important information.
For example, some websites advocate the inch-per-gallon rule while others advocate "12 square inches per inch of fish." These two guidelines are very different with regard to both underlying principle and the net effect. Additionally, neither one works depending on what is meant when the "How Many?" question is asked; sadly, neither rule covers all aquarium conditions and both rules have shortcomings. One of their most significant handicaps is an inability to place fish in aquariums of an appropriate size. That is, even though both agree that a 10-inch fish can be placed in a 10-gallon aquarium, both omit that a 10-gallon is not actually big enough for such a fish to turn around. This is a huge problem for new aquarists in that almost all of the "rules" are actually guidelines that work only if the conditions are fairly specific (i.e., the fish have to be of the right type, of the right size, and in the right tank).
So what is the solution? How are new aquarists supposed to know how many fish they can keep? The truth is that there is no answer to these questions that is short and easy, despite how simple the common stocking guidelines appear. Stocking aquariums appropriately not only requires a fairly specific question (specifying lifespan, life conditions, basic fishkeeping philosophy, etc.) but also requires a good deal of knowledge and common sense. Therefore, new aquarists should not be asking how many fish they can keep. Instead, they should be requesting information: What factors affect stocking capacity? Are there any good books out there that go over fish needs in detail? Who can I talk to about my specific setup?

Stipulations for the Solution

Regrettably, few new aquarists actually want to take the time to set up their aquariums based on hours of research. While I loathe this "give-it-to-me-now" mentality that some people have, I cannot ignore the simple fact that fish die when people make bad decisions. I hate to see innocent fish die just because new aquarists happen to be uninformed. I know they are just fish, but people should be responsible regardless of an animal's size or type. Furthermore, an unsuccessful aquarium is like throwing away money in that most aquarium systems cost about fifteen dollars per gallon (depending on size, equipment, and fish). Even if fish are not as important as I make them out to be (and they probably are not), most people can appreciate the prospect of not wasting their hard-earned cash. The net result of these considerations is that I have made, with the help of much more experienced fishkeepers, a device that can give new aquarists a rough estimate of how many fish they can keep based on several qualifiers.
Before anyone uses my device (any version of it), it should be noted that the following guidelines were used to design it:
  1. Owner Responsibility: My stocking theories emphasize the responsibility of the aquarist in providing adequate care and do not let an aquarist shift blame to exterior conditions. Since the aquarist made the choice to keep the fish, the aquarist is liable for the fish from the point of purchase onward.
  2. Consistent Positive Results: The operating theory behind the device is proven to work in general or for the significant majority and returns a repeatable result under otherwise dynamically similar conditions.
  3. Prevention of Negative Outcomes: The practice of using the device is aimed at preventing possible problems and tends toward helping fish thrive rather than just survive.
  4. Stress Reduction: My device assumes that stress has a bearing on a fish’s lifespan. As such, stress is reduced whenever feasible or possible.
  5. Mimicry of Natural Conditions: My device is made with a basic understanding of fish’s physiological needs as per their natural habitats.
Since the "How Many?" question is prefaced with the above stipulations, most users will find that my device tends to error on the side of caution rather than possibility. That is, my device will prevent "iffy" situations even if they do happen to work for some people. Furthermore, my device is not the complete answer to all freshwater aquarium questions. Instead, it is designed to primarily handle the "How Many?" question (though it does touch base on many other considerations). Lastly, the device was designed to be used at specific points along the path to creating an operational aquarium. It only gives viable results if certain initial conditions are met before it is used (it is not much help once the user has made a significant mistake).

What is the Device?

The device I am referring to is FishsheetA7V1, a spreadsheet that has many features designed to assist new aquarists. Why a spreadsheet? Simple, spreadsheets can be used by most computers that have Excel, can referrence thousands of data points, and are relatively user-friendly (read directions, think about the directions, and answer the questions). Of course the Fishsheet series does have some limitations (which I am trying to work around), yet these limitations are not so severe as to render the concept useless. FishsheetA7V1 contains over 240 different types of fish and has specific data for each one. For instance, it "knows" temperature requirements, minimum tank sizes, and some versions (FishsheetA6) even provides lists of compatible fish (though it should be mentioned that the lists are not flawless).
Link to FishsheetA7V1 and other Recent Fishsheets

Using FishsheetA7V1 in its Proper Place

Before FishsheetA6 is used, the following timeline of aquarium set up should be reviewed:
  1. The aquarium is not of advanced intentions (it is not a breeding aquarium, not designed to house picky species, and not designed to house the fish temporarily (the fish should be kept for their full lifespan)) but is well-selected for the functions it will perform..
  2. Appropriate equipment is procured. FishsheetA7V1 only works if a filter is used and the primary filter should not be live plants, algae, an algae scrubber (even though they are quite effective), or residual flow devices.
  3. The aquarium is cycled. Caution: cycling can be a long process requiring several weeks.
  4. FishsheetA7V1 is downloaded and used to compare various fish combinations.
  5. Once several combinations are selected, the aquarist must research the germane fish to ensure that the fish will not harm each other under the conditions in the aquarium (FishsheetA7V1 cannot tell if a user has enough decorations or if every species is perfectly compatible).
  6. Fish are added to the aquarium in small groups over the course of several weeks. Generally, new aquarists do not need to add any more than one quarter of all the fish they plan on keeping in a period of two weeks. This means that most aquariums will take a couple months to completely stock with fish. The only notable exception to this guideline is shoaling fish, which do best if added as an entire shoal rather than fragments. It should also be noted that some cycling techniques do allow for complete stocking in as little as one week, but such techniques may not be suitable for beginners.
  7. When adding fish to the tank, they should undergo an acclimation process to help them adjust to the new water temperature and perhaps the new water chemistry.
  8. If fish die or are returned to the pet shop for some reason, FishsheetA7V1 can be used again to quickly "try out" new combinations. All combinations should be researched before being implemented.
To see an example of how to use FishsheetA7V1, click here.