I noticed a yellow stain on it

Here are a few tips to help you prevent the yellowish hue from becoming a recurring problem:

Seal properly: Make sure your salmon is sealed airtight before freezing. Vacuum sealing works great, but if you don’t have one, use plastic wrap and place the salmon in a freezer bag.
Label and date: Always mark the date your salmon was frozen so you can see how long it’s been frozen. The USDA recommends eating frozen fish within 3-8 months for the best quality.
Recycle: If you’re buying salmon in bulk, try to use the older fillets first and stick to a “first in, first out” mentality.
In the end, my yellowish salmon turned out really well. I grilled it to perfection and served it with garlic asparagus. The family didn't even notice the difference. It was still juicy, delicious, and disappeared within minutes.

So, the next time you notice your thawed salmon is yellowish, don't panic! Do a quick smell check, cut off the discolored part if necessary, and then continue with your favorite salmon recipe. Chances are,