Yep it is Dallisgrass. Good luck.

How do I get rid of it?

Actually, that appears to be variety of goosegrass. Goosegrass is a common weed in Fescue and often gets mixed in with the Fescue seed, which is why it's important to check the analysis of the seed and make sure that it has a guaranteed 100% weed free analysis.

As for getting rid of it, in Fescue selective control is tricky so be very careful. Fusilade II is what I would use in conjunction with a non-ionic surfactant. Also, I would go at a minimum rate and make two to three applications 14 days apart to minimize turf injury. Tenacity is another choice, which has less risk of injuring the turf, but may not be as effective. If you use the Fusilade II, it can also be used safely around most ornamental shrubs for grassy weed control. It also kills Bermuda very effectively.

Also, make sure to use a good pre-emergent, such as Dimension this Spring to avoid new sprigs coming up this season.

Here is a link that might be useful: .