Yes, in a little over a month, we’ll release our 10 survivors in the North Carolina mountains near the headwaters of the Green River. I’ve gotten permission to release the fish at a private summer camp, the Green River Preserve. The fish are growing quickly-I’ll post some new pics or video soon.
We are down to the “lucky 10.” Of course, this was not by design. These fish seem to be healthy and are feeding aggressively. We have not lost a fish in over a week now. It is hard to tell from the photo below, but the largest of our fish are now 2.5-3 inches in length. Almost as long as a child’s finger…
February Fingerlings
And, here’s a little video of them also…
So, the conditions in the aquarium are stabilizing once again. Nitrates are slowly coming down with water changes. A few more fish were lost this week, so there are about 15 or so left in the tank. Now, a new threat. With all the stress over the last two weeks, the fish have developed some sort of protozoan, fungal, or bacterial disease. Their are tiny white streaks on the edges of their fins. At first glance, I thought we had a very common disease know as Ichthyophthirius multifilis, or ich, or white spot. On second glance, I really think it may be fin rot. Regardless, I have found some treatment solution and have applied it to water the last 3 days. Crossing my fingers that this will work.
Well, it looks like we’ve managed to stabilize the nitrogen levels and pH in the tank. The ammonia spike (and resulting nitrate spike) was caused apparently by overfeeding, and then dead fish collecting in the filter on the system. After many water changes later, things seem to be ok. Only about 20 fish remain. Hopefully, we’ll be able to better control conditions and keep these guys for release around April. They are about to enter their 4th month (since conception), and the largest fish are about 2.5 inches.
One of our 20 survivors
Apparently, we had too many fish (100?) and too much waste build up over the long school holiday. We’ve lost about 60-70 of those fish over the last few days. Even with water changes, it is tough to keep things in balance right now. I knew we could not sustain those numbers as fish got larger, but wow. So, the goal now is to keep 15 fish for my 15 students to release in a NC mountain stream this April. If not, time to start over with new eggs…
So, it’s holiday season here and I’m taking some time off to recover from surgery. The fish are set up with an automatic feeder. During my one visit, they seem to be thriving and growing like crazy. I’ll post an update in January. Happy New Year!
Yes, the larger trout are eating the smallest. There is a pretty wide range of genetic variety in our trout population. The largest parr are about 2 inches, and the smallest are still under 1 inch. While I think I am providing ample trout chow for all the fish to thrive, the largest and most aggressive trout seem to disagree! Look carefully at the two pictures below. While they are a bit blurry, you can see two different views of a larger trout with a tiny tail sticking out of his mouth:
First signs of cannibalism!
Yum!
Check out this short video of our parr feeding. My they have grown!
Well, it has been about 10 weeks now since these trout were conceived. The fish now have 6-8 dark bands on each side called parr marks, and are now called parr instead of fry. These bands may have some function as camouflage for the young fish in the wild. Although the picture is a bit fuzzy, you can see these marks on some of the larger fish in the foreground:
Note parr size using ruler
If you look carefully, you can also get some sense of the genetic variety in these fish. The largest of the parr are about 1.5 inches, and the smallest around half that. As the fish get larger and hungrier, I imagine we may start to witness some cannibalism.
So, after almost a month in the tank, the fry have reached about an inch (average) in length. Notice how they aggressively “hit” the food at the surface.
It will be interesting to see how many of the approximately 100 or so fry survive over the next few months. I’m doing regular water changes, but as the fish eat more and more food, they make more and more waste.