Newly captured reef fish are spectacular in color and form. No other animals in the world can compare with the vivid coloration, beauty and diversity that are found on the coral reefs. In the natural environment, water conditions are perfect, the diet is complete, and, unlike in our aquariums, unnatural stress is absent. Because of these, the animals that live there remain healthy and their immune systems function properly. This is not the case with captive fish. Generally, the diet they receive lacks many of the needed nutrients, the water quality is less than ideal, chronic stress is a problem and their immune function is suppressed. Hence, captive fish soon begin to exhibit the telltale signs of shortcomings in their care. Of course there are exceptions to this scenario, but to what do we attribute their eventual early death?
Diet and nutrition
First, let's look at diet. What sort of symptoms should we be aware of that would indicate that an improvement in diet is necessary? Better yet, how can we prevent dietary problems? Poor growth is an indicator of improper diet, or poor water quality. Substandard water conditions cause stress and therefore stunt growth. Depressed behavior is another warning sign of poor diet, undesirable water conditions, or chronic stress. Eye problems are a common occurrence in fish suffering from nutritional deficiencies. This can take the form of blindness, cataracts, or other ophthalmic lesions. It can also lead to vertebral anomalies, fin erosion, gill hyperplasia (enlargement) and skin hemorrhages. Then, of course, there is the ultimate symptom of dietary deficiency: death.
What causes dietary deficiencies? Improperly stored foods, a monotonous diet, not using foods that adequately substitute for the natural diet and not feeding often enough or providing enough food per feeding. Do you buy fish foods in large quantities but cannot use it all within a couple of months? This may initially sound economical, but it is not. Many foods quickly lose their nutritional value. Unless kept frozen, buy only what you can use within two months. Frozen food can be kept longer. Refrigerate all non-frozen foods, even flake or freeze-dried food.
How many types of food do you offer on a regular basis, one, two, or four? Fish need more variety in their diet than that. Do you know what the natural diet is for each species that you keep? Do you offer foods that are similar to their natural diet (i.e. vegetable matter such as dried seaweed to fish that are herbivores)? Do you use more than one type of food in each category, such as a variety of green foods, seafood, crustaceans, worms, etc.? How healthy would you be if you only ate red meat and bananas? Your fish need a good variety of foods just as you do. Do you rely on flake and freeze died foods as the staple of their diet or do you provide frozen or fresh seafood and live foods? Generally, frozen, fresh and live foods are more nutritionally complete than flake or freeze dried foods. Do not feed freshwater feeder fish to saltwater predator fish. They cannot digest these foods properly and foods originating from freshwater do not contain essential elements needed by animals that live in saltwater.
How often are you feeding your fish? Some fish have rapid metabolisms and require several small feedings a day. Others, such as many predators, should not be fed daily. They need time to assimilate their foods and will overeat. Overfeeding can cause them to become impacted or they may accumulate too much fat. Some fish, such as tangs, are grazers that require an almost constant supply of food.
Understand the natural feeding habits of your stock. Do you feed more than the fish can eat in a few minutes? If so, you may be feeding too much at one time. Do the fish voraciously consume all the food quickly? When fish begin to get full they start eating and swimming more slowly. If any of the fish have pinched looking abdomens, they haven't been getting enough to eat lately. If the area behind the eyes and along the spine is looking a bit thin, the fish has not gotten enough to eat for some time now. Faded colors can also indicate a needed improvement in diet.
Regularly soak the foods in a good vitamin supplement. Alternate this with Selcon™ that will provide essential HUFA or highly-unsaturated fatty acids. HUFA spoils quickly so keep it and vitamins in a refrigerator.
Why are correct parameters and water quality so important? Fish are much more dependent upon their environment than land animals. Water parameters and quality affect the body temperature, metabolism and blood chemistry. Gill tissues are very sensitive but play a large part in performing four essential body functions: osmoregulation, acid-base balance, respiration and ridding the body of nitrogenous wastes. Anything that affects the gills can negatively alter these vital functions. The significance of water quality in relation to fish health management can scarcely be overplayed.
Frequent water changes are the best way to keep water quality high. Test all water parameters regularly and record the results for future reference. Use only well aerated and aged saltwater when making a water change. Mixing the water at least 24 hours ahead of use will give the salts time to completely dissolve and allow the water chemistry to stabilize. This will also prevent irritating sensitive gill tissues when making water changes. Do not be skimpy about making frequent water changes. These water changes can solve many problems. Consider a water change as the first course of action when you think there may be a problem with the water chemistry or anything seems to be bothering your fish or invertebrates. I know it sounds simple but you may be surprised at how often it works. Keep a fresh batch of saltwater ready at all times, because it may save your animals in the event of an emergency.
What sort of impact does stress have on your animals? Stress has a significant impact on the beauty, growth, reproduction, digestion, immune function and overall health of fish. The more you understand the causes of stress the better you will be able to control and prevent it. Stress can be placed into four loosely fitting categories: human interference, water pollution, extreme changes in the physical environment and animal interactions.
Human interference includes things such as netting, crowding and handling. Water pollution includes things such as nitrogenous waste, toxins, chemicals, and high levels of dissolved organic matter. Extreme changes in the physical environment include things such as temperature fluctuations, rapid changes in salinity, lack of oxygen in the water and changes in pH. Animal interactions include aggression, which can take many forms. Competition for a mate, space, food, protecting a spawn and predators are common causes.
How can we prevent stress in our fish? The most obvious step is to educate yourself. Learn about every animal's requirements for its habitat. What is the environment like where this animal is found in the wild? Do you have a brightly-lit tank but your fish are cave dwellers? Do your fish prefer a deep sand bed but your tank has a bare bottom? Emulate the natural environment in every way possible. Do you fully understand the water chemistry of your aquarium? Do you know how to keep all of the water parameters at optimal levels? Do you know what animals will be compatible with each other? What do you know about their natural diet?
Observe each animal on a daily basis. By doing so, you will become familiar with their behavior and appearance and be able to quickly spot any changes. These changes may come well before water tests detect anything is out of line.
Education is the recurring theme here and the key to success. If you do not educate yourself, you simply cannot know what you are not aware of. Keeping your animals in top condition begins and ends here. Never stop reading aquarium literature. Learning is a fundamental element of the hobby and should be an ongoing process. Join an aquarium club, because you can learn from other experienced aquarists. Your investment of time and money will pay dividends in healthy animals and increased satisfaction and success with the hobby.
10 Tips for Optimal Fish Health:
- Learn about the needs and natural environment of every animal prior to purchase.
- Feed a wide variety of foods.
- Offer foods that are similar to that of the animal's natural diet.
- Supplement the foods by fortifying them with vitamins and HUFA.
- Make frequent water changes.
- Age and aerate water for 24 hours or more before using it for a water change.
- Check and record water parameters regularly.
- Observe each individual animal daily and watch for behavior changes.
- Emulate the animals' natural environment in every way possible.
- Learn about the causes of stress in fish and how to control them.
Terry Bartelme is a veteran of over thirty years experience with marine aquariums. He has authored more than one-hundred articles for various aquarium magazines including Advanced Aquarists Online, Freshwater and Marine Aquarium, Tropical Fish Hobbyist and other publications.