Time to be alert!

Reports are flowing in that suggest some schools are near or even at the early swim-up stage. These next two or three weeks could prove critical. Here's a question Green Mountain Valley School's Meg Lyon sent in yesterday:

In the last day or so nearly all our fish have been swimming up (see picture below). We also noticed a spike in the ammonia level, to about 2ppm. We're planning a water change (more on this below), but should we start feeding too? Our DI is at 82.45.

 Here's how I responded.
I'd say that probably you should offer a bit of food to those who swim up. 

This next period could be important, especially for noticing when the trout want to feed. (If at all possible, you should be checking your tank at least every other day, even during the vacation week.)

I'm not sure I'd advise a water change at this point. The main reason to do a partial water change is because of  high nitrate levels. Raised ammonia levels may well mean that your tank is starting to "cycle." Premature or excessive water changes might only delay this. 

If indeed your tank has started to cycle, after ammonia levels have gone up, the nitrite level should increase, then the ammonia level should decrease, then nitrate level should increase, then nitrate level increase. 

I also suggested that Meg read the article titled "What ammonia, nitrate, and nitrite levels are okay?" in the Water chemistry and trout health" folder on the Google Docs site (link below).

Water chemistry and trout health

If your Cumulative DI is close to Meg's, this is a time when it's particularly important to monitor the tank closely, looking for signs that the fry are ready to feed.