NUTRITION AND DIET

Nutrition:

• Protein should make up 15-55% of a standard diet, depending fish species and size. 15%-30% is optimal for herbivores, and 45% is optimal for carnivores. Omnivores are in between. Young fish require around 50% or more for vigorous growth, but be careful not to overdo it.
  • It is necessary for growth and repair of cells as well as body tissue. It is an important source of energy, but too much will cause excess ammonia production.
    • Protein Sources: Fish, shrimp, squid, krill, etc…
• Lipids (fats, fatty acids, and oils) provide energy and allow the uptake of fat soluble vitamins, as well as other important nutrients.
  • Extra fats are stored in the body, but too much can affect the liver’s ability to filter and cleanse the blood.
    • Lipids Sources: Fish and shrimp oils, most fish and invert meats will also contain lipids as well as protein, fat, minerals, and vitamins. Some plant based oils may also provide lipids.
• Fat should make up only 3%-8% of a diet, depending on species and size. A herbivore needs no more than 3% of fat in the diet, while a carnivore no more than 8%. Omnivores are the in between.
  • Saturated fats are harmful and should be excluded from the diet.
  • Polyunsaturated fats can be helpful when conditioning a fish for breeding. These are easily digested.
  • Excess fats can cause disease and early death, affecting the liver.
• Carbohydrates should make up less than 40% of the diet. Adult fish can handle as much as 40% without ill effects, but it should not be fed in excess.
  • Carbs are a good sources for energy and important bodily functions.
  • Carnivores have little use for carbs in the diet, and are not processed very well or efficiency. Omnivores and herbivores, however, are capable of processing these very well and use them to their best ability.
  • Too many carbs can cause growth issues with fish.
  • Higher percentages of carbs can cause a reduction in the absorption of other nutrients, vitamins, and minerals.
  • There should be more carbs in a herbivore and omnivore diet than there should be in a carnivore’s, but they should not be completely left out.
• Fiber should make up 4%-10% of the diet. Carnivores cannot digest fiber, and it should stay no more than around 4%. Herbivores can have more, around 5%-10%, which omnivores in between.
  • Fiber is important to aid in digestion. It can be used when a fish is constipated or facing swim bladder disorder.
• Minerals vary in the amount that should be provided in the diet.
  • They are important for bones, teeth, amd scales.
  • The most important minerals in a fish’s diet are calcium and phosphorus.
  • Iron, iodine, magnesium, sodium, potassium, copper, and zinc are all necessary in the diet.
    • Mineral Sources:
      • Calcium: Hard water parameters, bone/meat meal, cuttlebone, oyster shells, eggshells, etc.
      • Phosphorus: live plants (planted in the tank), bone/meat meal, eggshells, etc.
      • Most minerals are found in sufficient amounts in commercial fish foods.
      • Eggshells are a good source for potassium, calcium, and phosphorus.
• Vitamins vary in the amount that should be provided in the diet.
  • Most prepared foods will quickly lose their vitamin contents. Using supplements such as Vita-Chem (available for freshwater and marine) is beneficial in aquariums, since it helps to maintain proper vitamin levels in the diet/water. It can be dosed both orally through soaked foods or directly dosed into the water, since it can be absorbed through the skin of the fish.
  • Every vitamin has its own important functions. The most important vitamins to include in a fish’s diet are: A, D3, E, K, B1, B2, B3, B5, B6, B12, C, H, M, and inositol.

Vitamin Functions and Deficiencies:

Being able to identify deficiencies of vitamins and understand the functions of those vitamins is important to being able to formulate a proper diet for your fish, and improving the nutritional content of their diets.

The following is taken directly from fishdeals.com’s vitamin deficiencies section. (http://www.fishdeals.com/fish_diseases/vitamin_deficiencies/) See REFERENCES AND SOURCES for proper citation.

Fat Soluble Vitamins

• Vitamin A
  • Functions: - normal vision, cell growth and resistance to infection
  • Deficiencies: - poor growth, poor vision, abnormal bone formation and hemorrhaging at the base of the fins

• Vitamin D
  • Functions: - calcium blood levels (?)
  • Deficiencies: - unknown

• Vitamin E
  • Functions: - antioxidant, may play a role in muscle cell respiration
  • Deficiencies: - anemia and poor growth

Water Soluble Vitamins:

• Thiamine (B1)
  • Functions: - aids growth, digestion and fertility, nervous system
  • Deficiencies: - poor appetite, muscle atrophy, convulsions, loss of equilibrium and poor growth

• Riboflavin (B2)
  • Functions: - vision, protein metabolism and enzyme functioning
  • Deficiencies: - photophobia, cloudy lens, dim vision, abnormal colouration of the iris, striated constrictions on the abdominal wall, dark pigmentation, poor appetite, anemia and poor growth

• Nicotinic Acid (niacin, B3)
  • Functions: - plays an important role in lipid, protein and amino acid metabolism
  • Deficiencies: - loss of appetite, poor growth, lesions in colon, erratic motion and weakness, edema of stomach and colon

• Pantothenic Acid (B5)
  • Functions: - adrenal functioning, cholesterol production, normal physiology and metabolism
  • Deficiencies: - poor growth, sluggishness, clubbed gills, loss of appetite, hemorrhagic skin and cellular atrophy

• Pyridoxine (B6)
  • Functions: - plays a vital role in enzyme systems and protein metabolism
  • Deficiencies: - nervous disorders, fits, loss of appetite, poor growth, rapid and gasping breathing, flexing of opercles and hyperirritability

• Cyanocobalamin (B12)
  • Functions: - enzyme systems, cholesterol metabolism.
  • Deficiencies: - poor appetite, poor growth, anemia and dark pigmentation

• Ascorbic Acid (C)
  • Functions: - enzyme systems, bone, tooth and cartilage formation and healing
  • Deficiencies: - hemorrhagic shin, kidneys, liver, intestine and muscle tissue, eye lesions and scoliosis of the spine

• Biotin (H)
  • Functions: - enzyme systems, purine and lipid synthesis, oxidation of lipids and carbohydrates
  • Deficiencies: - loss of appetite, poor growth, anemia, skin lesions and muscle atrophy

• Choline
  • Functions: - good growth and food conversion
  • Deficiencies: - poor growth, poor food conversion, hemorrhagic kidney and intestine

• Folic Acid (M)
  • Functions: - blood cell formation, blood glucose regulation and fish metabolism
  • Deficiencies: - poor growth, lethargy, dark skin, anemia and fragility of the caudal fin

• Inositol
  • Functions: - cell membrane permeability
  • Deficiencies: - poor growth, distended stomach, skin lesions and increased gastric emptying time

• p-Aminobenzoic Acid
  • Functions: - unknown
  • Deficiencies: - no abnormal indication in growth, appetite and mortality

Nutrients and Products Often in Commercial Foods:

• Wheat Germ Meal:
  • Consists of wheat berry, bran, and other parts of wheat. This is mainly composed of carbohydrates, since it is made from wheat.
• Whole Fish or Fish Meal:
  • Fish meal consists of dried, ground fish which is not used for human consumption. Mainly small marine fish, but a small amount would be bones and left over offal from processed fish.
  • Scaled, and cut fish mixed into the diet. This is whole fish, not left overs. A good source for various nutrients.
• Spirulina:
  • A blue-green algae which is very nutritious, a human superfood. Rich in protein, amino acids, carotene, and Vitamin B12.
• Garlic:
  • Can help to repel Ich (ick) and internal parasites from a fish’s system. It’s also often used as an appetite stimulant, although some fish tend to show disinterest in garlic.
  • Using garlic supplements in the diet can be very helpful for the prevention of disease and illness, as well as to aid the immune system and its functions. Garlic Guard is a commonly used supplement which appeals to fish.

Fisheriessciences.com (http://www.fisheriessciences.com/fisheries-aqua/factors-that-can-lead-to-the-development-of-skeletaldeformities-in-fishes-a-review.php?aid=6678) has a helpful resource about skeletal deformities, which highlights various nutrients such as calcium and phosphorus.