We ended up releasing the trout one day ahead of the planned Earth Day event. The conditions of the Cold River weren’t unideal. The fear had been that the release location would live up to its name and it would be too cold for the tiny trout. When we tested it the week before the temperature had been just over 39 degrees. The trout could have probably survived being that cold of a temp but their main food sources, small macroinvertebrates and certain larva, would not have been available yet. These little fish already have a lot going against them and releasing them just in time to starve would not be particularly helpful for their journey. Thankfully on the day of the short notice release the aptly named Cold River had reached a balmy temperature of 43.7 degrees fahrenheit. A little bit short of the desired 45 degrees but still within the range of a chance at survival.
We didn’t want to release the trout so early. If possible we would have liked to wait for some warmer water and better weather. Not a last minute coordination with a rainstorm close on our tails. But it had to be done to give the little fish at least some chance at survival.
From the very beginning we had issues with the tank pH and ammonia levels. In the first few days of the fish move the pH started to climb up into the realm of 8.0+. Not immediately deadly, the trout could survive some degree of basic water, but something to definitely be worried about. Especially in conjunction with the ammonia levels that were creeping up. The higher the pH the less ammonia needed to be deadly. In the tank ammonia was produced by waste on the bottom of the tank, food either eaten or uneaten, and dead fish. With the stress of the move producing casualties and me being unsure of the right feeding levels it wasn’t too strange that these were the first problems to pop up. But with careful tank monitoring, reduced feeding, and the prompt removal of any lost fishy souls; I was able to reach some sort of balance in the tank. And for about a week and a half things were pretty good. And then I tore a hole in one of the filter bags.
Every Sunday I would take the two filter bags out and clean them as best I could. They were always a little grimy but they still worked just fine enough. So when I tore a hole in one of the bags trying to get it a little cleaner it wasn’t a huge deal. I had exactly one replacement filter bag so I used that. At least this is where I think I went wrong because in the days following that the pH took a nosedive and kept diving. I had the ability to test pH down to 6.0 and it was a struggle to keep it above that. The trout can handle some fluctuations and some degree of acidity but not to the extent of what was happening in the tank. I couldn’t do a big water change either, the pH of the office tap water was too high .So I was stuck with doing water changes a few times daily with a mason jar and using some aquarium products to try and keep the pH up. What I think happened was there was fungus on the replacement bag. Until then I was using all of the same equipment and following the same process with every step of the tank care. Some water molds can come from the breakdown of organic matter. It could have been a relic on the filter bag or it could have been from just waste in the tank despite my best efforts to keep it as clean as possible. Either way, at the same time as the pH drop I started finding one or two deceased with white fluff growing on them.
There were probably more things I could have done. There are treatments with dyes and salts that I didn’t have access too and could have potentially been too extreme for the trout to handle. But most importantly there wasn’t enough time to try and obtain the treatment and introduce it.
So we made the decision that some survival would be better than hoping for a miracle. One day early we packed up the trout in my grubby Subaru. Me and my fellow AmeriCorps member Sarah wrapped two five gallon buckets with ice packs and blankets and drove 40 minutes with the windows down to meet up with GMCG’s Education Coordinator at the release site on the Cold river. We were trying to keep the water as cold as possible to make acclamation as easy as possible for the trout. It still took twenty minutes of slowly adding river water to the buckets to match temperature. And then it was time to say goodbye and good luck. We scouted out a calm slow moving bit of water without any obvious predators and cupful by cupful released the endlessly tiny juvenile brook trout into the river.
I’m not sure if I was happy to see them go or just glad that there were trout still alive to be released. I was convinced on numerous occasions that I would come into the office to find a tragically still fish tank. In just under a month I took over 60 tank measurements, sent a number of panicked texts, changed water by the jar full, and spent a whole lot of time just staring at a whole lot of little fish. There are good years and there are bad years with trout in the classroom tanks. Even in the wild trout tend to follow a type three survivorship curve. Produce a lot of young in the hope that some survive until adulthood. I know I didn’t do a perfect job. But for an emergency trout adoption at short notice during a global pandemic without any prior experience and with limited resources I think I did alright. I learned a lot at least. The only thing left for me to do is to clean the tank and equipment for next year. When I hope it can be a classroom looking after the fry again instead of one very anxious AmeriCorps member. I have to wait though for better weather so I can work outside. The recommended method for cleaning the tank is a diluted bleach solution and I’m still worried about ammonia.
Ellie is a full-year LRCC member serving with Green Mountain Conservation Group. You can read more about Ellie here!