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Selection a use of a microscope for aquarists

SELECTION & USE OF A MICROSCOPE FOR AQUARISTS

by Bob Blaho 

GCCA’S CICHLID CHATTER — JANUARY 1999    

The first thought that pops into many readers’ minds may be, “why bother?” The intent of this article is to show you why. We hope to establish for you, whether you have or might have a need for use of such an instrument. We’ll show what choices of microscopes you have, how they function, and what purpose you, as an aquarist, may have for this tool. Some of this material is a compilation from various sources and some is based on personal experience. Some specific sources, for more information, are listed at the end of this article.

First, what is available out there? The answer to that question is also a question. What do you need to accomplish? If you’re looking to gather more information about your aquarium environment, this is one way to do it. Visual information can provide us with facts that we can respond to. The first thing most of us do when we walk into a room, which has one or more aquariums, is to take a closer look at them. We look at what types of fish are in them, what types of plants are planted, and the condition of the fish, plants, or water. In other words, what we can see! The limit, to what we can see, is our eye. We frequently aid (especially as we get older) our eyes with prescription glasses or magnifying glasses. Those of us that do extremely fine detail work use a loupe or binocular magnifier. These are instruments that are simple, inexpensive, and usually easy to use. They let us take that closer look to get the information that we’re after. The lenses we use to see and identify what we’re looking at, come in a variety of choices. Selection of your lens type is usually determined by the level of magnification and detail needed to accomplish your job. As the magnification and quality level rise, so does the cost. Each level of capability has its purpose. The microscope, the com- pound light optical version, is only a multiple lens design to help us see items closer up. Its capability for magnification covers the range of 20-1000X. The electron micro- scope versions which go beyond 1000X will not be discussed. The compound light microscope then is what we’re concentrating on. It answers the question, “why bother?” If you have the desire to take a closer look at your aquatic environment, a need to identify what might not be normally visible, then you probably would benefit from using a microscope.

Selection of your microscope is again based on your needs. The toy versions for children are probably the reason that many people don’t proceed further. Any optical instrument is only as good as the precision and quality of the glass it uses. A microscope should be bought as a lifetime investment, much as a high quality camera system. Buy the best you can afford, to do the job you want, or may want to do. Look for the magnification range you need in selecting your eyepieces and objectives. Buy those models that conform to one of the best recognized standard configurations. These are the Deutsche Industrie Norm (DIN), most common, or Japanese Standard (JIS). Stick with DIN standard compo- nents and you’ll have the best of all worlds. This will enable you to select a greater variety of components for your microscope that will be inter- changeable and expand your capa- bilities (and also its resale value). A typical compound microscope consists of these basic components: an eyepiece lens (ocular), tube, objective lens, stage, stand, condenser, and light source. Look at a drawing or photo of a typical compound microscope and you will have no problem in identifying these parts.

There also is a choice in variety for each of these items. Eyepieces can be monocular, binocular, or trinocular. The monocular variety is the least expensive, since it uses only one eyepiece. Typical types of eyepieces can be Huygenian, Ramsden, Kellner, and Periplan. Each succeeding class of optics increases in quality and cost. Objectives also are available in the degree of optical correction desired. These are achromatic, semi-plan, and planar. Achromatic objectives provide a flat field of view in about 65% of the center of the image. Ramsden eyepieces, often called Wide-Field, are usually used with the achromatic objectives at higher power. A look at a catalog listing selection will quickly establish what you wish or need to afford. The best way to go, is to buy a microscope that comes as a system, so you can expand your choices later. An eyepiece in 10X Wide- Field and turret arrangement with your selection of objectives in 4X, 10X, 40X, and 100X will get you started for most purposes. This gives you the capability of 40X, 100X, 400X, and 1000X. Most of your aquarium work will be done between 40X and 400X. 1000X (oil immersion) is used for more advanced cellular and bacterial work. The stage of your microscope can be plain with spring clips to hold your glass slide or have a mechanical stage that adjusts for the short distances a slide is normally moved. For bright field illumination, the light source can be external, using a mirror to direct the light to the slide, or be built into the base to provide illumination. With either light arrange- ment, alternate types of lighting may be desired. This could be the basis of another article in itself. The question is, at this point, what should one consider as the basic minimum setup? Consider these items:

  1. Make sure that the microscope has a solid stand, with fine and coarse focusing and a monocular tube.

  2. The eyepiece should be 10X to start, with a selection of 5X, 15X, and 20X oculars added as needed.

  3. A turret holding at least three objectives, achromatic in 4X, 10X, and 40X will be sufficient to start.

  4. The stage can be equipped with only removable spring clips or have the mechanical stage to allow more precise placement of the slide. Removable mechanical stages can be added later if desired. This option starts at about $70.00 and goes up in price, based on capabilities.

  5. A light source, such as a microscope lamp or even a simple high intensity desk lamp, unless the illumination is built in.

  6. Beneath the stage should be a condenser lense that can be focused to properly illuminate the slide. A diaphragm to control light intensity and a filter holder should be part of this package.

The Swift M3200 (see Figure 1, next page), is an example of a good starting package. A basic package for the above, new from a catalog or outlet, will start at about $200.00 and can go higher based on quality, choice of lenses, and other options. A good used microscope can be found around college campuses and in papers like the “Trading Times.” This would enable you to buy a better quality instrument at the same or lower cost than a new one. Going up in price range will obtain a binocular, four objective turret, a mechanical stage with built-in illumina- tion, microscope starting at about $500.00 used. A Bausch & Lomb binocular mi- croscope (see Figure 2, next page) is an example with these features.

A good quality microscope of this variety, new, will start at about $800.00 and rapidly escalate based on optics and brand name (Leica-$1500, Zeiss-$2000). Figure 3, an American Optical dual binocular head microscope, is an example of some of the specialized features available. You can expect these additional capabilities to add to the microscope cost.

So now that you’ve selected what you think is the best microscope for you, what do you do with it? You will have to use it and acquire some experience in develop- ing your techniques. Books and manuals are available in most libraries covering just about all aspects of microscopy you may want to learn. Concentrate on devel- oping your basic skills. Use your microscope for checking the quality of water, identify the microscopic plants and creatures that inhabit your aquarium along with your fish. If you have baby fish, which require live food, check for paramecia, rotifers, daphnia, and other micro food cultures in your aquaria. Keep tabs on how the cultures are doing. See what other helpful or detrimental organisms are present. Do you keep egg layers? Pluck an egg and put it under your lens to see if it is fertile. If you see no life (movement) in the egg, it is not fertile. Then just continue with your process of elimination to establish what caused the infertility. Do you have health problems with your fish, plants, or snails? Check to see what’s differ- ent with the healthy versus the unhealthy. Identify your problem hosts so you can take a targeted approach to correcting the situation. The books below can give you more ideas for use of your microscope.

Several books you may want to look at are as follows:

Using the Microscope - A Guide for Naturalists by Eric V. Grave, Dover Publications, 1984

Exploring with the Microscope by Werner Nachtigall, Sterling Publishing, 1996

Hunting with the Microscope by Gaylord Johnson and Maurice Bleifeld, Arco Pub- lishing, 1980 3rd Edition

Diseases of Aquarium Fish by Robert Goldstein, T.F.H. Publications, 1971 Handbook of Fish Diseases by Dieter Untergasser, T.F.H. Publications, 1989 Discus Health by Dieter Untergasser, T.F.H. Publications, 1991
1998 Optics and Optical Instruments Catalog, Edmund Scientific Co., 609-573-6250

These sources will help you develop your techniques and aid in identifying what you’re looking at. The Edmund Catalog will be an aid in establishing beginning choices and prices. As you gain experience, you’ll add to your library those periodicals that cover your areas of interest. The knowledge you gain can be useful not only in your hobby as an aquarist, but also in any other areas where you want to take a closer look at your environment. ■

If this article was of interest to you and you would like more on lighting techniques, slide staining and preparation, photomicrography, or other areas of interest related to microscopy, let me or your editor know. We may start an ongoing series of articles if there is sufficient interest. 

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