I have been experimenting with taking photographs of goldfish for a few years now. This web site shows the results of these efforts. The site also shows the results of some professional efforts. Sadly, the difference in quality is still quite marked. I am getting better, but Ive got a long way to go.
If I had to claim a "specialty", it would be taking in situ pictures. By that, I mean taking photos of fish in whatever container they are in, rather than posing them in a specially setup photography tank. I have asked two of perhaps the best goldfish photographers in the world, Man Shek-hay and Fred Rosenzweig, about their techniques and secrets. One common element in both their methods is that they use aquariums setup precisely for the purpose of taking photos. I have not done this normally, though I have once or twice with my own fish.
First thing is equipment: I use a 20-year old Nikon FG SLR with a Vivitar flash unit and macro/zoom lens. This is okay, though an auto-focus SLR is nice if you want to take pictures rapidly (which you need to do to get that one, great shot). I started out trying to use a tripod and cable shutter release, where I would get everything setup and then wait for (or herd) the fish to come into position. This is not very effective in my experience. I got lots of "almost" perfectly framed shots i.e. the fish centered but with the head or some other important body part out of frame. Hand holding the camera has proven to be the way to go. Of all the possible equipment, the macro lens and the flash have proven to be the most important capabilities for me.
A digital camera is ideal, if the web or desktop publishing ("DTP") is the destination for your photos. I use film and a scanner, because I have multiple uses for the pictures. But I have had several experiences where key shots just didnt come out and I never knew until it was too late to recover. A digital camera would have let me see the results instantly, avoiding any unpleasant post-developing surprises.
One nice aspect of using a scanner to digitize a Web-destined photo is that you can select just the part of the photograph that is of interest and make that part as large as desired. So, for example, photos I have taken of goldfish eggs and young fry to put on my Web site have been scanned just to emphasize the small features of interest. With a good quality print and scanner, you can turn a one-inch square part of a print into a surprisingly clear full-screen sized image.
Above: a scanner enlargement of about four square centimeters of print
If you go with film, I use both slide and print, depending on how I think I will use the pictures. For fish club talks or magazine publications, slides are best. But for most all other uses prints are most convenient. For print film I have had very good results with the 400 ASA Kodak MAX film; it seems to perform as advertised. One thing that can be very surprising is the interaction between artificial lighting and film. Colors can come out in photos looking very different than your eye sees them, usually washed out and tinted towards yellow or blue. This is one reason that the use of flash is important, as the result under flash illumination is usually very close to what your eye sees.
All right, enough discussion. You have a camera in hand and a tank of fish in front of you. What do you do? If you are using a flash, not too much special; you just need to keep the camera at an angle of at least 20-30 degrees off from straight on to the glass. This is to keep the flash reflection from bouncing back directly into the camera. Turning down the room lights, which could produce reflections off the glass, is also a good idea, though the brightness of the flash illumination will usually drown these out if you cant eliminate them during setup. Leave the tank lights on, so you can focus.
Above: oops, there's the flash unit! (for once, this is someone else's photo)
One thing that was important for me was setting the aperture fairly open (say f8 for my slow telephoto lens). I dont know why, but if I let my camera set everything automatically, I ended up with a high percentage of shots that didnt come out, being underexposed (flash synchronization problems, I guess). Probably unique to my setup, but the advice I would give is to get a roll of film (you can use cheap film and developing for this) and just experiment with different settings. This will give you real insight into what works and doesnt work with your photography equipment, reducing the chance of surprises when you really want a shot to come out. Dont forget to write down what you do, so you can compare the results to the settings later.
One "side effect" of the technique described above, using a flash unit and taking the picture through the glass at an angle, is that it can distort the image of the fish. Usually the result is to foreshorten the fish; this is due to the refraction of light through the water/glass/air interfaces. If you are going to use the picture in a digital form, almost any image manipulation software will let you stretch the picture to correct this. But it can lead to quite weird looking fish. The worst cases of this have been in acrylic tanks in my experience.
Above: this funky looking Panda Demekin is in an acrylic tank and appears shorter than it really is.
Recently, Ben Tan from Malaysia sent me some really nice pictures of his fish. I asked him about his technique. He uses a remote flash that is triggered by his camera's own flash going off. He points his camera flash straight up and then has this remote flash above the tank pointing down. This eliminates the flash reflection issue that I have to worry about. It also doesn't illuminate the background, giving a more pleasing dark background. I am looking forward to experimenting with this technique; it could be a real step forward.
Above: Ben Tan's photo of his Ranchu. Note the great lighting and the dark background.
I want to emphasize that this "in situ" technique is the quick and dirty approach. The result will never be as good as that from a custom aquarium setup intended specifically for fish photography. Ive tried to use special setups a few times with mixed results. The key points of Fred Rosenzweigs technique are to use natural sunlight for the illumination and to place black cloth (like a towel, for example) over the photographer, camera, and the side of the tank you will be taking pictures through. Using sunlight gives very attractive saturated colors in the images of the fish. The cloth minimizes the reflections on the tank side that you are shooting through.
Above: this picture of Bravo was taken in natural sunlight. Note the nice color saturation and the naturalness of the tints.
This sounds simple enough, but when I have tried casually to setup something like this, it has been surprisingly difficult. Some of the problems, as examples:
This all is not intended to discourage people from trying this approach. Im just pointing up a few of the difficulties that must be overcome to get really good results. But Im sure once you get a method down, the results will more than offset the labor involved in creating the proper setup.
I mentioned earlier that you could correct the foreshortening of the fish in a digital image, using photo manipulation software. I have to admit that I have also used this type of software to improve color saturation, increase contrast, and in general make an "OK" picture into a very attractive digital image. I think this is entirely reasonable to do; keep this in mind if you intend to put your pictures on the Web (either your own page or sending them to me) you may be a better photographer than you thought, given a little digital post-processing help.