Evidently I don't know how to do two pictures at a time.
{{gwi:82031}}

It's way to wide bladed to be creeping red fescue. It looks like tall fescue to me, but I'm not the best at identifying grasses from pictures. However, the comment that it cuts when you run your finger up the blade sounds like K31.

Why do you think it isn't K31?

That looks like an improved variety of tall fescue.
The improved varieties are very desireable for home lawns whereas K-31 is not an improved variety and is more suitable for cow pastures and that sort of thing.

The care regimens for tall fescue and zoysia conflict with one another. If you care for the zoysia during the summer when it is actively growing, it will choke out the tall fescue. If you care fore the tall fescue during the fall and spring when it is actively growing, it will displace your zoysia.

You will want to pick one or the other if these grass are planted in the same place. Seeing as how you are in zone 7/GA, you are at the extreme limit for both species of grass. Neither one is going to do "great". IF you pick the tall fescue, it will be green year round and very shade tolerant but suffers in summertime drought and heat. If you pick the zoysia, it makes a nice durable turf in the summer months but is brown or not very vigorous the rest of the year and it will spread into your flowerbeds or other landscaping you may have.
Zoysia needs to be cut more frequently in the hot weather and tall fescue needs to be cut more frequently in the pleasant fall and spring mild weather.

Thanks, everyone. We are in the midst of a drought and I'm willing to have anything that's half-way nice to grow and help keep the soil in place. If this is a decent fescue, then I won't mind if it takes over the Zoysia. The fact that it came up and is spreading at a fast rate kind of had me worried. I don't want some sort of weed.
bpgreen, I guess I always thought one fescue seed would sprout into just one individual plant, not into a tuft, a creeping tuft at that. You see how much I know about grass.
I may take a wait and see attitude. Thanks to you all.

It might be poa trivialis- I can't tell from the photos. I assumed it is tall fescue because you said you planted tall fescue seed.

To clarify, tall fescue will not outcompete your zoysia in the long term. It may do it over the cool season but once summer kicks in the zoysia can aggressively spread just as the fescue is stressed and it probably won't recover. At least not at a rate that will look good.

Tall fescue does not spread via rhizomes like other grasses in georgia. It starts out as a baby clump then gets to be a daddy clump and after a while if there is nothing competing with it will get rather large. Instead tall fescue spreads by seed that may be carried in by the wind or birds and often is considered a lawn weed.

If you want fescue permanently, you have to remove the competition and go so far as to make the site more favorable. You can see how nice it looks in the cool season so millions of people in georgia choose tall fescue. You cannot beat that lush dark green color.

Zoysia sod is somewhat expensive so if you have a sodded lawn it's a big decision to REPLACE that with something else.

If you have a sloped area, those are typically not very easy to maintain. You may consider doing what a lot of people do with tough slopes in georgia which is to remove the sod altogether and plant juniper shrubs like parsonii and sargeant and grey owl junipers and to mulch the area with pine straw. It looks beautiful- no maintenance except for the pine straw and you won't ever have to futz with the lawn there again.

To answer your posting subject, anything that you do not want growing in your lawn is defined as a weed.

For example, Saint Aug to me is a weed cause I dont want it in my lawn.