Microscopy

[Lolafish]

Many budding aquarists may never give a second thought to adding a microscope to their arsenal of diagnostic tools.  You may think "why would I possibly need one?"  Consider this; many ailments that plague our beloved aquapuppies often share symptoms with a whole range of other illnesses or infestations.  For instance, gill flukes can present symptoms in your fish like flashing, lethargy, or surface panting (to name a few) but a fish that might be in the early stages of an ich infestation way present the same behavior.  Like wise a fish with the dropsy symptom may be suffering from an infection of any one (or a combo) of bacteria.  Using a microscope one can specifically identify the fish's assailant and can then eliminate it with the most effective method.  With out the microscope you're basically shooting in the dark when it comes to some problems, throwing meds at your fish and hoping it will work. 

I know what the average person is probably thinking right about now.  "I don't know a thing about microscopes.  I wouldn't even know where to begin in choosing one."  Well to keep it simple, I recommend buying the highest quality instrument that suits your needs.  You don't need something that can blow up atoms just something you can use to identify bacteria and common parasites. Make sure that the microscope has a solid stand, with fine and coarse focusing and a monocular tube. The eyepiece should be 10X to start, with a selection of 5X, 15X, and 20X oculars added as needed.  A turrent (aka the nose piece) holding at least three objectives, achromatic in 4X, 10X, and 40X will be sufficient to start. The stage can be equipped with only removable spring clips or have a mechanical stage to allow more precise placement of the slide.  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.

Here's a diagram to illustrate all that technical mumbo jumbo I just threw at you.



Once you have your new microscope here are the basic steps in how to use it to view specimens:

1. Turn on the power
2. Close the iris diaphragm or choose the smallest iris aperture in the disk
3. Rotate the turret until the lowest optic is in position
4. Adjust the optic control knob to bring the optic as close as possible to the slide with the speciman on it
5. Begin to look at the slide through the ocular and slowly turn your control knob until the mucus appears
6. Rotate the turret to choose a higher powered optic.

Tip: Do not look for the parasite at the highest power straight away.  Always start out at the lowest power with the least amount of light.

Now you know how to work it but you're thinking "what am I looking for?"  Well pictured below are many of the common things you may find on (or from within) your fish and in your tank.

Gill Flukes




MPEG movie of a fluke under the microscope at 100X magnification

www.koivet.com/movies/fluke2.mpg
© Dr. Erik Johnson

Costia

www.koivet.com/movies/costia400.mpg
© Dr. Erik Johnson

Tape worm egg (usually found in stool sample)




Ich protozoan




Nematodes (there are literally hundreds of different species of nematodes.  Not all pose a threat to your fish)




There are books and manuals available in most libraries covering just about all aspects of microscopy you may want to learn.  Most of those depict just about any kind of specimen you may find on your slide to aid you in identifying.

Using the Microscope - A Guide for Naturalists by Eric V. Grave
Hunting with the Microscope by Gaylord Johnson and Maurice Bleifeld
Diseases of Aquarium Fish by Robert Goldstein
Handbook of Fish Diseases by Dieter Untergasser

[Kaida]

Some of us use a microscope to aid in diagnosing illness and parasite infestation in our beloved aquapuppies.  Preparing a skin scrape is really fairly simple and uncomplicated.  To start with WASH YOUR HANDS before you touch any thing.  It's very easy to contaminate your slide with whatever is living on your hands.  Plus you should always wash your hands before handling your fish anyway.  If you have any open cuts or sores on your hands it's advisable to wear latex gloves (or their equilivent  if you're allergic) since your fish can transmit several different ailments through these openings.

Skin Scrape
Make sure your slide and cover slip are clean and dry.  With the slide to be used, gently scrape along the side of your fish from just behind the gill plate in the direction of the scales or a site around an ulcer or blood-shot area.  These are good locations to find parasites and unwanted bacteria.  Once you have a bit of mucus on the slide you can push it to the center with another cover slip or slide. With the mucus in the center of the slide lower a cover slip onto the mucus and lightly press down on it to spread the mucus and make into a thin layer.  Dry the rest of slide, being careful not to disturb the cover slip and mucus.  Now its ready to be viewed! 

Gill Scrape
This is not something I recommend a novice to do.  It's very easy to severely injure your fish if you don't really know what you're doing in this procedure.   If you are looking for gill flukes you can often find them in a skin scrape just out side of the operculum (gill cover).