Black gravel n Corys

I changed the gravel in my tank from crystal glasses my wife put in there when she started the tank to black gravel.
I have a male betta n 2 albino corys in the tank. 10 gallons tank fully cycled.
Since I put the black gravel in the tank the corys aren't too active anymore like they used to.
Can the black gravel made the 2 corys sad or unhappy ? Or I'm just losing it

@Tyler777, you are not as you said,, 'losing it.' It is my opinion that your tank's habitat was disrupted with the replacement of all of the previous light substrate with new the, dark substrate. Your water parameters might be within tolerance which is good, but for sure, your Corys are wondering what happened? Some aquarists think Corys can only live with a fine sand substrate but in nature, depending on the species, they are found in fine sand, gravel and even mud and leaves & muck. So I think your Corys are adjusting to a significant change in their home. Do you have any overhead cover for them such as a cave? Think about it, they went from a substrate where they were somewhat transparent to being 'center stage' in the tank.

This is my wife 36 gallons tank that she used black diamond coal slag in. So far so good. Corys seem to be find so are the koi betta females .I'm still not sure bout that stuff buy I'm watching the tank closely to see if there are problems with the cotys or water parameters . So far so good

Beware. Gravel has to be extremely clean and smooth for corys. Otherwise it can cause bacterial issues that erode their barbells.
A soft, smooth sand is really best for them. They feed by sifting through sand. I don't think they're really happy without it. Even if you can't have all of the substrate be sand, maybe you could place a bowl of sand in the aquarium for them to sift through.

Well after several weeks with the corys living n eating on that black coal sand I have to admit they're doing fine non of the corys seems to b or act sick or hurt due to the coal black sand.
They're swimming all over the place n eat everything that falls on the bottom. I added 2 more albino corys there . Now I have 5 in that tank along with 7 koi female bettas n 5 normal female bettas. They're all doing just fine n happy. But I will keep checking that black coal sand

They may look fine and it may seem like they are doing their natural duties. But they eat by browsing the sand, the food is separated and the sand is removed out their gills.

They can’t do this with gravel.

I have 10 Yoyo Loaches and they eat in a very similar way.

In the long run you will be doing damage