Radiography and other imaging techniques facilitate the non-destructive evaluation of fish for a variety of special purposes. These techniques may be used in the systematic analysis of fish morphology where the size and shape of the vertebrae, fin rays and other skeletal elements can be thoroughly examined and measured without destroying the specimen. Radiography can also be a valuable instrument in the evaluation and etiological determination of morphological abnormalities or disease syndromes in fish. In addition, special radiographic techniques, such as barium contrast studies may become more useful in the future as fish health professions become more familiar with these techniques. Unfortunately, the full potential of radiographic evaluation in fish medicine is presently limited due to a number of reasons. Persons who are familiar with piscine anatomy are generally not familiar with radiographic technique, and conversely, persons familiar with radiographic techniques and evaluation are not generally familiar with fish anatomy. In addition, few radiographic studies of normal specimens are available in the literature as a basis for comparison.

One objective of this project was to determine whether contrast radiography could be used clinically to evaluate the intestinal tract of fishes. One ml of 30% Novopaque (a 60% barium solution diluted one-half with water) was administered per o.s to large, healthy goldfish. The fish were removed from the water without the use of anesthesia at various time intervals (0, 15, 30, 60, 120, 180, 240, 360 and 480 minutes) for exposure of radiographic films. Several exposure techniques were evaluated, with the best radiographic films being produced using a kVp of 42 and a mAs between 5-6.4.