Frequently Asked Questions

 

When should the trout be allowed out of the breeder basket?

It is generally agreed that trout should remain in the breeder basket as long as possible, even after some start to jump out on their own. As a general rule, the alevin should stay in the breeder box for between three and four weeks after hatching is complete. Once all the trout are able to swim freely and have been feeding actively for at least two weeks, they are likely to be strong enough to navigate the currents of the tank and can be released into the tank.  

 

How do I let the trout out of the breeder basket when it is time?

Gently remove the breeder basket from the sides of the tank and lower it slowly to the bottom. The trout can swim out from there. This allows some trout to remain protected in the breeder basket for a few more days. Tip the basket very gently to remove any lingering fish before removing it from the tank.  Be sure that the filter intake is covered with a mesh bag to prevent small fish from getting suctioned into the unit. 

 

Some of my hatched fish are not eating. Some of my fish are deformed. Is this normal?

Yes. During the growth process, some fish will die. Some fish may survive initially only to die later because they never begin to eat. Other fish will be deformed and very often will also die. This is a natural part of fish reproduction. It is not normal, however, for very many or most of the fish to die. If this is the case, there may be a problem with the tank environment. 

 

What do I do with my eggs in an emergency?

In an emergency, eggs can be preserved by placing the breeder box in a container of water from the tank and putting the container holding the eggs into a cooler containing de-chlorinated ice or one or more ice packs that have been washed in de-chlorinated water. Keep measuring the water temperature in the breeder box to determine the amount of ice or ice packs needed to keep the eggs around 50°F. Do not add ice directly to the eggs. Place the ice or ice packs around the outside of the container holding the breeder box.  However, do not permit any ice or water from the melting ice to mix with water in the container holding the eggs. Note: Whole Foods sells ice cubes made from de-chlorinated spring water.

 

Can I keep eggs or fish in a household refrigerator?

No. Refrigerators are not an acceptable substitute for the tank environment. Because most refrigerators operate between 35F and 40F, they are far colder than the tank. 

 

My eggs have hatched. What should I do with the eggshells?

The discarded eggshells will decompose naturally in time. If they appear to be hosting fungal growth, they should be removed and disposed of. Just as with living eggs, they might turn opaque white or may take on a fuzzy appearance. If this is the case, remove them. 

 

What do I do if I find dead eggs or dead fish?

Remove dead eggs and dead fish as soon as possible using a turkey baster or siphon. Do so at least once a day, and even more often during critical periods or as needed. Remove fish waste and decaying waste matter (e.g. discarded food) when you clean the gravel per instructions in Chapter 6. This process alone is very important in keeping the remaining fish alive. Poor cleaning is very often the root cause of excess fish death. 

 

Why are so many of my eggs or fish dying?

Death is a natural part of fish development. Everyone should expect to lose eggs and fish. The exact survival rate is highly variable and based on many factors.  A sudden spike in mortality can indicate a tank problem. It is also worth noting that there are two naturally high-mortality periods: first during the egg stage and then again when the trout first need to learn to feed.  Some fish never learn to feed and simply starve.  

 

What is a normal death rate?

Death rates are different from one stage to the next. With eyed eggs, a high survival rate is expected because they come from the hatchery tempered and treated against fungus. The loss of most of your eyed eggs suggests a problem. In Vermont, the highest rates of mortality have occurred at or just after the swim-up stage, when fish that didn’t learn to eat die as “pinheads.” As the fish mature, survival rates improve. By the time fish have all learned to eat, death should be an uncommon event. Losing many free-swimming fish is, above all else, a sign that the tank environment is not healthy. As they grow, fish produce more waste, so diligent cleaning and water changes may be needed more often. 

 

My alevin are very active and are pushing other fish into the corners of the basket. What does this behavior suggest? Should I be feeding them more?

This is normal activity. At this stage, young trout prefer dark corners. Putting some opaque material over the breeder box may help to reduce the amount of light these fish are exposed to. UV light can be harmful to eggs and alevin. Fish at the alevin stage do not need any food. When at the end of the alevin stage the fish begin to feed, start with small amounts.  See Chapter 8 for guidelines on feeding the trout.

 

Trout are being sucked into the filter. How can I prevent this?

Place BioMax media bags or similar screening over the filter intake as recommended in Chapter 3.

 

How sensitive are the fish to temperature changes?

For best results, the tank water temperature for trout should be maintained as close as possible to 52° F. Fish can handle small fluctuations of a few degrees, but sudden changes of almost any scale will be stressful. Rapid changes of 50 F or more are a serious threat to trout survival.

 

What should I do if all the fish are lethargic, unmoving at the bottom of the tank, gasping for oxygen at the top of the tank, or don’t respond to food?

See Emergency Instructions below.

 

Why are my fish or eggs dying at an abnormally high rate?

Poor water quality from insufficient cleaning or water changes is among the most serious threats to fish health. It is essential to perform de-chlorinated water changes according to the guidance in Chapter 6 of the Manual. Other causes of fish death might be sudden pH or temperature fluctuations, insufficient bacteria, lack of aeration, and chemical exposure. High ammonia, nitrite, or nitrate concentrations can result in sudden fish death. Frequent water testing will show if the tank water is experiencing ammonia issues. Dealing with ammonia spikes is covered under the Water Quality section below.

 

What if I come in and find that many of the trout have died?

1. Remove healthy fish first and put them into a bucket filled with de-chlorinated water and 1 or 2 bottles of frozen de-chlorinated water prepared for emergencies.

2. Put a battery-operated aerator or tank air stone into the bucket.

3. Turn off the chiller and the filter.

4. Remove as much water from the tank as possible (at least 80%).

5. Leave filter intake covered.

6. Clean tank sides by scrubbing with a clean sponge and siphon the gravel. Remove as much fish and food waste as possible.

7. Refill tank, remembering to treat the water with NovAqua Plus

8. Turn the chiller back on.

9. Cool the water to 520-540 F. with de-chlorinated ice or leak proof freeze packs externally washed with de-chlorinated water.

10. Drain the filter and clean the foam pre-filter material.  Do not replace more than half of the Bio-Max or Chemi-Pure media, which is part of the tank’s biological filter

11. Turn the filter back on.

12. As soon as possible, add Nite-Out II in accordance with instructions for its use. See Appendix E.

13. Put fish back in tank.

 

I ran out of food. What do I do?

Contact a TIC volunteer or Coordinator

 

CHILLER

What do I do if my chiller stops working?

Try to maintain water temperature by putting one or two of the previously prepared bottles of de-chlorinated frozen water in the tank. Contact your VTTIC coordinator. Continue adding plastic containers of frozen de-chlorinated water to maintain the tank water temperature at about 520 until a replacement chiller arrives.

 

Obtaining an Emergency Replacement Chiller 

A spare chiller and controller may be available for emergency use. Please get in touch with your local CVTU coordinator or support member to arrange for its delivery and installation.

 

 

WATER  QUALITY

Do I need to age tank water before first filling the system?

No. The tank should be filled with tap water treated with NovAqua Plus, which will remove chlorine and heavy metals.

 

My tap water is discolored. Is this ok?

All water will have some color. Most often the water may be colored a faint green or white. Tap water that is not acceptable appears very cloudy or has a strong chemical smell. If this is the case, an alternate source of water should be obtained. 

 

Cloudy tank water 

Cloudy tank water probably indicates too much decaying matter. This may be from dead fish, leftover food, or a filtration problem. The best way to handle this problem is to:

 

1. Conduct regular water changes.

2. Clean the tank of all solid material (fish and food waste) by siphoning the bottom of the tank.

3. Make sure the filter is functioning properly and that water is flowing through it. 

4. Clean filter components, if needed, with de-chlorinated water but do not use soap or chemical cleaners.

5. Keep reducing the amount of food until fish consume all they are given within 5 minutes. Excess food should be removed and discarded.

 

How should I conduct water changes? What is the right amount of water to change?

Water changes are an important part of tank maintenance to provide a healthy environment for the trout. A general rule of thumb is to change about 10 gallons of tank water every week (20% of the volume of the tank), using water de-chlorinated with NovAqua Plus. A gravel vacuum/siphon is an efficient way to clean the tank and remove water at the same time. Twice-a-week cleaning, i.e., removing 5 gallons of tank water each time, will keep the tank clean as well as generate a weekly 10-gallon water change. However, as stated in Chapter 6, it is best to use chemical tests and the overall health of the fish to determine the size and frequency of water changes.

 

Should students wash hands before touching tank water?

When working in or around the tank, students must wash their hands, preferably with de-chlorinated water, and carefully rinse off contaminants such as soap and lotions because trout are extremely sensitive to chlorine and other impurities. They should also dry their hands thoroughly. 

 

Should students wash up after contact with tank water?

Yes. While tank water is not particularly hazardous to students, they should clean their hands with soap and warm water. Please do not use soap until all tank work is done. 

 

What is an ammonia spike? What can I do about it?

An ammonia spike is one example of a chemical imbalance in the tank environment. These are serious threats to fish health. The tank filter and its bacterial population help reduce problems like this, but they cannot work alone. The best way to prevent chemical imbalances in the tank is to clean the tank regularly and change the water. All debris such as food, waste, and dead fish should be removed as soon as possible. There is no substitute for regular cleaning and water changes. See Chapter 7 of the Manual for a description of the nitrogen cycle and Chapter 6 for guidance on cleaning the tank and changing the water.

 

Can I use AmQuel Plus or ammonia removal grains to prevent ammonia spikes?

They may be used only in a dire emergency and if a large water change doesn’t reduce the ammonia. These chemicals tie up the ammonia in the water, rendering it harmless to the fish. However, by tying up the ammonia, it deprives your biological filter (the “good” bacteria) of the food it needs to live and grow. So in the long run, while you have reduced your ammonia, you are killing off your long-term ammonia reducer (your biological filter). Please consult your TIC volunteer or coordinator before adding any other media to the tank or filter. If water tests indicate that ammonia levels are excessive and fish are exhibiting signs of ammonia stress a large water change is recommended.  This is generally necessary only in extreme cases. 

 

POWER  FAILURE

What happens if there is a power failure? How much time do I have? 

It is important for the fish to have as stable a water temperature as possible as well as proper filtration and aeration. Short downtimes of an hour or two probably will not harm the fish or change tank temperatures or other parameters significantly. However, loss of power over a weekend or even worse, over a long vacation, will likely be fatal to the fish.  

 

What should I do if the power must be turned off?

The custodians who are authorized to turn the power on and off should be informed that the trout system needs constant power. If constant power is not possible, see if you can cycle the power. This means running the chiller for two hours on, then two hours off. This is better than simply letting the tank sit all day without power. It is best to prevent any such problems and carefully maintain the tank environment. The priority in an emergency is getting the tank environment back to normal. No emergency procedure can replace the stability of a working tank.

 

TANK

What tools are needed for tank installation?

The tools for tank installation are: a utility knife to trim the polyethylene foam insulation board if not already provided by CVTU, scissors, a marking pen, and two clean five-gallon buckets to assist in filling the tank and for water changes. Rinse the buckets first and then do not use them for anything other than tank water

 

How can I help keep a stable tank temperature?

It is important that the chiller always be on and set to the appropriate temperature of 52°FLimiting water changes to 5 gallons at any one time will help tank temperature stability, because using un-chilled water in a water change will increase the water temperature in the tank.

 

 

Why is aerating the tank water necessary?

Aeration of the tank is an important part of simulating a stream environment. The stream environment is not only cold, but also constantly moving and constantly mixed with air, providing oxygen for the trout to absorb through their gills. Because of this, the filter and air stone are both important.  That is why the filter intake and the surface of the air stones should all be clean and free of debris.  Positioning the outflow of the filter above the water surface will also increase dissolved oxygen.

 

The air stone aeration system produces a large volume of bubbles. These bubbles can interfere with the filter operation by filling the motor with air and causing it to “air lock” and fail. For this reason, there should be at least 4 inches between the air stone and the filter intake. Also avoid placing the air stone where bubbles can accumulate under the breeder basket and raise it out of the water. 

 

My tank is coated with a green slime. What is this? What should I do?

Green films or slime probably indicates the presence of algae. This will not necessarily hurt your trout and some teachers leave it growing. However, to remove it from your tank, please see Chapter 6, Section B5 in the Manual for instructions. To prevent further growth of algae, limit the amount of light entering the tank  Excess accumulation of nutrients in the tank will also cause algae growth. Periodic cleaning of the tank and the gravel will help remove algae.   

 

Should I get a lid for my tank?

Cover the tank top with foam insulation material to prevent objects from falling in and trout from jumping out.

 

Why does my tank need insulation?

Insulation provides a darker, more stable environment for the fish. It will also reduce the amount of work needed to maintain the water temperature, save electricity, and limit the amount of time the chiller will need to run (See Chapter 3, Section A, 3)

 

What kind of insulation can I use?

Use one-inch thick solid core polyethylene foam to cover the top, bottom, back, front, and both ends.

 

I am using the same tank system I had last year. What do I need to do to make it ready this year?

Assuming that end-of-year cleanup procedures were followed, start the school year by cleaning all parts of the tank system with warm water. Do not use soap on any part of the tank. Rinse thoroughly and allow time for the parts to dry completely. Also replace the air stone and the disposable filter media.

 

INSTRUCTIONS FOR EMERGENCIES

 

How can I inform custodians or other teachers about what to do if there is an emergency while I am away?

A written protocol for handling emergencies should be prepared by the teacher and discussed with the designated emergency back-up person(s) by the time the trout eggs have hatched. This document should include the following: 

 

1. Basic information about the tank set-up

1. The tank needs a constant flow of electricity.

2. The chiller is a critical component of the tank set-up because it keeps the temperature of the tank water at about 52°F. This is a requirement for trout survival. The chiller is located ____________. (fill in the correct location).

 

2. Instructions for keeping the trout alive under emergency conditions. The trout need cold water to survive. An emergency condition is usually a temperature spike, i.e., tank temperature has risen to 60° or more, generally caused by a power outage or, less often, a chiller failure. A massive and sudden ammonia spike can cause a major fish die-off very quickly even if all the equipment is properly operational. Rarely does a major problem arise from an aerator or filter breakdown.

 

     a. What to do if the chiller stops working:

 Unplug the chiller, wait five minutes, then re-plug and restart the chiller.  If the problem is a power outage, a tripped circuit breaker, or some other system failure, unplugging the chiller won’t help. In any case, lower the temperature of the tank water by placing two or three previously prepared one- or two-liter plastic bottles of frozen de-chlorinated water into the tank

The plastic bottles are located : _______________________.

         

With a net, located _________________________________, remove all dead fish and uneaten food from the tank. If more than six fish are dead, do a 5-gallon water change. Two 5-gallon buckets and a siphon, located___________________________ are available for a water change. Siphon off 5 gallons of tank water into an empty bucket and discard. Fill a 5- gallon bucket with tap water. Treat it with NovAqua Plus according to directions on the bottle and slowly empty the un-chlorinated water into the tank.

 

b. What to do if the aerator stops working: If the pump is still working, unplug it from the outlet. Disconnect the tubing at the outflow.  Blow into the tubing to see whether the airflow is restricted. If it is, disconnect the air stone and blow through the tubing again to determine whether the problem is with the air stone or the tubing. If the tubing is blocked, the problem is probably dirt in the check valve. The best solution is to keep a spare check valve handy attached to replacement tubing to connect to the air stone. Replacing the old check valve and old tubing with the spare check valve and tubing assembly makes for an easy and inexpensive solution.

c. What to do if the pump is not working: Disconnect the pump, wait ten minutes for it to cool or reset, and plug it in again. If the pump still doesn’t work, replace it as soon as possible.

d. What to do if all the equipment is working and more than 6 fish are dead:

Remove dead fish and follow the procedure in 2a above to remove and replace two 5-gallon buckets of water.

 

Whenever a sudden fish die-off of more than 10 fish takes place, please consult CVTU TIC Coordinator and support persons