Fish & Aquatics | Aqua Management

Fish & Aquatics | Aqua Management

Sudden Losses of Fish

When the majority or even the entire population of fish in a fish culture system die suddenly, the cause is usually an acute environmental stress. Possible environmental stressors include inappropriate water quality parameters. The most common cause of fish kill is probably depletion of dissolved oxygen. Depletion of dissolved oxygen may occur due to several reasons and often is predictable. Emergency aeration should always be available for intensive fish culture systems. Some common causes of oxygen depletion include sudden die-offs (crashes) of dense phytoplankton blooms, insufficient or no supplemental aeration at times of high oxygen demands, pond turnover and aeration system failure. Dense phytoplankton blooms may die at once (crash), especially when there is an extended period of low light due to clouds. Some people also mistakenly treat ponds with algaecides during phytoplankton blooms. A sudden crash of a phytoplankton bloom will result in oxygen depletion because of bacterial decomposition of the organic matter (from the phytoplankton).

The decomposition often uses all of the available oxygen. Sufficient supplemental oxygen must be supplied at times of peak oxygen demand. The most common time in ponds is when the water is warm and the fish are densely stocked. The phytoplankton use oxygen at night, which often leads to dangerously low dissolved oxygen concentrations during the night and early morning. Supplemental aeration should be added to ponds when this condition exists. The supplemental aeration should be enough to maintain D.O. within safe levels.

Pond turnover may occur at any time of the year. However, one of the most common times is in late summer when the water is very warm and oxygen demand is already high. Turnover is often caused by a sudden cooling of weather and a cold rain which cools the water close to the surface. The cool water on top is more dense than the warmer water below and causes the pond to turnover. Turnover often releases anoxic water from the bottom, which causes a lack of oxygen throughout the pond. Additionally, noxious gases, such as Hydrogen Sulfide, are sometimes liberated from the bottom. Some fish culture systems rely entirely on supplemental aeration or oxygenation to supply D.O. Many tank and recirculating systems are stocked so densely that the fish within those systems will begin to die from asphyxiation within minutes of a systems failure. Any system that depends on supplemental aeration or oxygenation should have a monitoring system that will sound an alarm in the event of a system failure.

Fish Quit Eating

The first sign of a problem is often a sudden decrease in appetite. If a group of fish suddenly quits eating, the cause is usually either an adverse water quality condition or disease. First, check water quality. If a water quality problem exists, rectify the problem. If fish appear unhealthy in any way (improper or erratic behavior, sores, etc.), they may be diseased. Send unhealthy-appearing fish to a pathologist for evaluation.

Water Quality

Fish are entirely dependent on the water in which they live and water quality often determines the success of raising fish. Many factors affect water quality. Among them are dissolved oxygen (D.O.), ammonia, nitrite and temperature.

Dissolved oxygen (D.O.) is the amount of oxygen present in water. The required D.O. level, which should be maintained, is dependent on fish species. In the event of dangerously low D.O. concentrations, fish often come to the water surface and gulp air because the D.O. is greatest at the air-water surface. When a period of dangerously low D.O. occurs, DO NOT FEED. Take action immediately to increase the D.O. to desired concentrations by emergency aeration, oxygenation or flushing with good quality (high D.O.) water.

Fish excrete nitrogen as ammonia. Ammonia exists in two forms, ionized (NH4+) and non-ionized (NH3). Non-ionized ammonia is extremely toxic to fish. Ammonia is measured by chemical assay as total ammonia (both ionized and non-ionized). The amount of total ammonia present as the toxic non-ionized ammonia is dependent on water temperature and pH and may be derived from a table. Ammonia is oxidized by bacteria in the fish culture system to nitrite.

Nitrite (NO2) is toxic to fish because it binds hemoglobin and prevents the uptake of oxygen. Acute Nitrite (NO2) toxicity causes fish blood to turn a chocolate brown color. If a dangerously elevated Nitrite (NO2) level exists, DO NOT FEED. A water flush of the system may be done if nitrite-free fresh water is available.Fish are cold-blooded animals and their body temperature is dictated by the water temperature. Tolerable temperature ranges and optimum temperature for growth are dependent on the species of fish grown. These numbers are guidelines only and may vary between different strains of the same species.

Johnson's Milling & Feed Inc. carries an array of animal health supplies for your veterinary needs, daily requirements, and emergency supplies, including supplements and formula. Please call us or stop in to learn more about our complete selection of animal health supplies.

LIVESTOCK HEALTH PRODUCTS

The following is a partial list of the products we have available for cattle, equine, goat, poultry, sheep, and swine:

Wormers

  • Paste
  • Injectable
  • Feeding Block
  • Boluses
  • Pour On
  • Pellet Feed Additive

Insecticides

  • Sprays
  • Roll On
  • Super Mask II
  • Dust
  • Feeding Blocks
  • Ear Tags

Supplements

  • Hoof Management
  • Nutritional Vitamins
  • Pain Management
  • Weight Builder

Antibiotics & Injectable Medications

  • Penicillin
  • Tylan
  • Liquamycin
  • Vitamin B Complex

Wound Care

  • Cut-Heal
  • NFZ Salve & Powder
  • Matrix Wound Care Products
  • Tri-Care


Livestock Vaccinations and More!

If you are not sure which product will suit your needs, just ask one of us. We will be glad to assist you.

Fish & Aquatics | Feeding the Food Chain For Bigger Fish

By Mark Griffin, Ph.D. and Gordon Ballam, Ph.D.
Purina Mills Research & Technical Services

Anyone who has ever spent a Saturday morning on their pond with a fishing rod knows what a thrill it is to feel a tug on the end of the line. The size of the thrill however, is directly related to the strength of the tug - the bigger the bend, the better. So wouldn’t it be great if the fish in your pond were as big as possible? Wouldn’t it be nice if your pond not only had bigger fish, but more of them?

It may sound like a fish tale, but it is possible - with good pond management and supplemental feeding of your fish.

Research has shown that ponds stay healthier, fish grow bigger and faster and sustainable per acre populations are larger with supplemental feeding. Ponds which naturally sustain a stocking population of 500 bluegills and 50 bass per acre can easily sustain 1,000 bluegills and 100 bass per acre with supplemental feeding. This remarkable difference is due in part to the fact that supplemental feeding affects a pond’s entire food chain.

Picture one of the old cartoons that showed a small fish being swallowed by a bigger fish who smiled all the way down the throat of an even bigger fish. This is the food chain action and illustrates one of the hidden benefits of supplemental feeding. At first glance, supplemental feeding seems to benefit only those fish such as bluegills, sunfish, hybrid striped bass, catfish, minnows and other species that directly consume the feed. And while it’s true these fish flourish - converting feed at a 2:1 ratio to produce a full pound of weight gain for each two pound of feed - they are not the only beneficiaries.

Feeding fish also supplies nutrients to the water which enable phytoplankton to grow. Since phytoplankton are at the very bottom of the food chain, they affect all the animals above them. When they thrive, other life flourishes.

At the other end of the food chain are the predators such as bass, walleye and larger catfish. They eat the bluegills, minnows, small catfish and other forage fish that have been supplied with supplemental feed. The food chain has now come full circle. By feeding the forage fish, you’ve not only provided yourself with a better catch when you hook a bluegill, you’ve also provided a better meal for your bass. As an added bonus, supplemental feeding also makes the forage fish population more plentiful because the larger size brought on by feeding encourages earlier breeding - sometimes as early as the first year. In the end, the result is an increase in the capacity of your pond to grow and maintain a greater number of trophy fish.

Ten Tips For A Successful Feeding Program

To help pond managers get started on a feeding program, Purina offers these ten tips taken from Purina’s Complete Guide to Pond Management:

  1. Start with fish bought from reputable vendors as they will already be trained to eat commercial feeds.

  2. Match the feed size to the size of the fish. If the fish vary in size, use Purina Game Fish Chow with multi-sized particles. The floating ration allows for monitoring of the amount of feed consumed. Feed only as much as fish will eat in 10 - 15 minutes.

  3. If training the fish to eat pellets is necessary, use Purina Game Fish Chow. It contains attractants to help train fish to eat a commercial diet.

  4. Begin feeding in the Spring when the water temperature rises above 55o F.

  5. Follow a routine each day, feed at the same time(s) and place(s).

  6. Choose a convenient location where you can throw the feed out over deep water.

  7. One feeding station is sufficient for small ponds. Ponds larger than 10 acres should have multiple feeding stations with one station for every 10 acres of surface area as a rule of thumb.

  8. To keep floating pellets from drifting into the shoreline build a simple, inexpensive feeder ring with 10-ft. sections of 1½”plastic PVC pipe. Connect the sections with elbow joints, then tie it to your dock or secure it to the bottom with weight tied to a string.

  9. Do not try to get too close to the fish when starting a feeding program. Stand back out of sight and move slowly. As the fish become accustomed to feeding you can begin to move closer. Some fish can even be trained to take feed from your hand.

  10. Never fish at a feeding station near or during feeding time. This will cause the fish to shy away from the feeding area.
Johnson's Milling & Feed Inc. carries an array of animal health supplies for your veterinary needs, daily requirements, and emergency supplies, including supplements and formula. Please call us or stop in to learn more about our complete selection of animal health supplies.

LIVESTOCK HEALTH PRODUCTS

The following is a partial list of the products we have available for cattle, equine, goat, poultry, sheep, and swine:

Wormers

  • Paste
  • Injectable
  • Feeding Block
  • Boluses
  • Pour On
  • Pellet Feed Additive

Insecticides

  • Sprays
  • Roll On
  • Super Mask II
  • Dust
  • Feeding Blocks
  • Ear Tags

Supplements

  • Hoof Management
  • Nutritional Vitamins
  • Pain Management
  • Weight Builder

Antibiotics & Injectable Medications

  • Penicillin
  • Tylan
  • Liquamycin
  • Vitamin B Complex

Wound Care

  • Cut-Heal
  • NFZ Salve & Powder
  • Matrix Wound Care Products
  • Tri-Care


Livestock Vaccinations and More!

If you are not sure which product will suit your needs, just ask one of us. We will be glad to assist you.