30 days before eggs are received #
Set up the bio-system in the tank, also called pre-cycling: Temperature 65°F (18°C). Start nutrient cycle by adding Stress Zyme or equivalent.
12-24 hours before eggs arrive #
Temperature down to 50-52°F (10-11°C).
Getting Eggs: Transport egg jar in the cooler padded with crumpled paper or foam to minimize the jostling and banging around, which can hurt the eggs.
Placing Eggs in the Water: As a rule of thumb, a tank can accommodate 100 eyed trout eggs for every 25 gallons of volume. Place the entire sealed egg container (which should be full of its own water) into the tank. This allows the eggs to slowly acclimate to their new temperature. After 15-30 minutes (when jar and tank temperature are within 1 degree), gently pour the eggs into the hatching basket.
After Your Eggs Are in the Water Eggs should be placed in a net- type breeding basket or vibert box.Keep the tank shadowed with a dark and/or insulating cover. You can remove it for viewing…or cut a viewing window. This cover gives darkness for the eggs, and helps keep the temperature down.
Egg Maintenance Eyed eggs are identifiable by their characteristic dark spots—each trout’s two eyes. Movement during delivery of the eggs can weaken the outer layer of the shell and cause weak spots or broken areas. These spots are vulnerable to fungal infection. Any eggs with white spots MUST be picked out. White spots are a fungus that spreads REALLY fast, pick out spotted eggs twice a day if possible—especially check last thing on Friday afternoon. Alaska Department of Fish and Game has a great explanation of what this fungus is. Outer shell must remain translucent, an egg with any opaque spots (or fully opaque) will not develop.
Uniform cloudiness can be okay, it might be just the trout development. The TIC folks in southwestern Virginia have made a great video about how to remove dead eggs carefully and effectively.
2-3 days after eggs arrive #
Hatching Most trout will hatch within 2-3 days of first egg hatching. Some eggs will not hatch properly and some alevin may not come all the way out of the egg. Any leftover eggs must be removed (or isolated—these likely will not hatch). The leftover shells float to the top of the tank or in the basket and fish enzymes will break down these shells and create foam—this is normal. Scrub the sides of the tank with an aquarium sponge to loosen this foam. During this alevin phase you may feel a jelly-like fungal growth around the inside tank surfaces and hatching basket. If you find this, wipe or scrape the surfaces with a sponge to send it through the sterilization and filtration system. When eggs hatch, alevin will lie on sides, with egg sack still attached…feeding from it. Soon they will “right” themselves, but remain low in the basket. As egg sac is consumed, they begin to rise.
1-3 weeks after eggs arrive #
Alevin (sac-fry)—(1-3 weeks) Length of time at this stage depends on the water temperature; warmer water causes fry to develop faster. Use a digital thermometer daily to make sure in-tank temperature is 50-53 degrees. Chiller consoles are notoriously inaccurate. Look for your odd trout and heart development, etc. Alevins can survive in a Petri dish under a microscope or hand lens short times. Some alevin don’t survive, and this is perfectly normal.
1 week or less after hatching: Swim Up Stage #
Swim-up stage— (one week or less) As yolk sacs disappear, some trout will start swimming around looking for food. More about swim-up here.
This is the time that you can remove the darkening cover from your tank or the front panel of insulation; at this point, UV light will not hurt the fish. Feed trout by spreading a miniscule amount of size 0 food near any swimming trout. Now is a good time to “boost” your tank’s nitrifying bacteria with a shot of Stress Zyme which can be added once a week .Now is the moment to add a mesh or pantyhose around your filter intake to prevent fry from getting sucked up into the filter intake. Once all fry are swimming up and have been eating, unhook the basket and drop it to the bottom of the tank. Strong, adventurous fish will swim out and timid, weaker fish will hide for a few more days, until they are stronger. Some fry don’t survive or learn to feed properly for various reasons: this is perfectly normal.
Non-feeding fish are called pinheads: large heads and small bodies. These fish should be removed and euthanized as they will never learn to feed and will eventually die.
6-8 weeks after hatching #
Fry stage—(6-8 weeks) A hatched trout, previously a swim-up fry, that is less than one inch in length and has learned to search for food and begin eating.
Try to ensure all of the fish are eating, this may require adding food on two separate sides of the tank. In general, feed tiny pinches 2-3 times per day. Every couple of days, carefully remove the mesh or pantyhose from your filter intake and shake out any debris collected (and let it get sucked up into the filter). This will keep your filter motor from having to work too hard, and minimizes guck.
Some trout never learn to feed and will die. Non-feeding fish are called “pinheads”—big heads, little bodies. These trout should be removed, as they will not develop. Every TIC classroom sees this mortality spike with the pinheads—it is VERY normal. Any leftover food that collects in one area MUST be removed 5-10 minutes later. A turkey baster is a great way to vacuum up extra food and waste. Continued leftovers mean that you are overfeeding and overfeeding can cause problems with ammonia levels.
Crisis notes: READ BEFORE TROUT TRAGEDY OCCURS Treat all of the water with water conditioners, such as Amquel Plus and Novaqua, when adding new water. If you come in and all fish are lethargic—WATER CHANGE. If you come in and all fish are unmoving at the bottom of the tank—WATER CHANGE. If you come in and your fish don’t respond to food—WATER CHANGE. During the first few weeks, initial ammonia spikes from overfeeding are likely. Water changes and some water conditioners are the only solution. It is also good to “boost” your tank with Stress Zyme as often as once a week. If you change your filter media, only change one section at a time allowing the bacteria from the remaining section to colonize the new media. The ceramic media should not be changed.
Until release day… #
PARR STAGE—(the rest of the time) Look for parr marks (the dark ovals or bands on the sides of young salmonid fishes) on the trout or salmon.
Small water changes with a siphon can happen every day with a 20% change at the end of each week. Clean 15 minutes after feeding. Always keep track of your water chemistry—water testing can help you with this. If any levels seem high, do big water change (20% or more).Be careful to watch the temperature during water changes and don’t let the tank temperature fluctuate more than 5 degrees or so.In an emergency, clean water is more important than temperature stability, though. Cannibalism can occur—the big fish do eat the little fish. If cannibalism is becoming an issue, then feed more often, so as to assuage hunger. Be sure to clean more often and do water changes, if you are feeding more often.
What if I come in to school many trout have died? What to do?
Any time you have loss of trout or your fish look lethargic, swimming sideways, etc – WATER CHANGE! Water changes remove toxic ammonia and nitrites. Initially, do a 50% water change with treated or dechlorinated water and stop feeding your fish. Monitor your chemistry daily. If ammonia and/or nitrites are still an issue, continue doing up to 20% water changes daily until situation resolves. Add as many bubblers to your tank as possible. The more O2 the better able your bacterial colony is at conversion of ammonia and nitrites. Feed fish very little, only as much as they can eat in a minute. Vacuum out any uneaten food.
It is vital that your tank establishes a healthy bacterial colony to move through the Nitrogen Cycle. The bacteria convert fish waste and extra food (ammonia) to nitrites and then nitrates.