Shrimp in hiding

[Harry]

For the last several days my shrimp have mostly been in hiding. I have created a good amount of caverns with lava rock so they have ample space to hide. But they generally swim about in great abundance. I'm wondering why they have just gone onto hiding. I do see between 6 to 12 shrimp come out, but they generally appear in much greater numbers. Is this typical?

[Harry]

I checked behind the tank and there are quite a few in hiding in the rocks and busy back there. Every now and then, one or two come out. Maybe it is just that time of year. I have a test kit on the way, but I believe the water is good. I did a 50% water change, just in case.

[Harry]

Some very small juveniles are coming out now. I still don't know what is responsible for this hiding behavior.

[Harry]

Water test kit shows no nitrites, no nitrates. I suspect the chaeto algae is soaking up the nitrates. Some of the shrimp are coming out, but very few. They are in the rocks and appear quite busy in there.

[Jim177y]

I suspect too much light been given in the tank.

[Harry]

Good thought. I have been cutting back on the light and more of them are coming out now. However, they no longer swim in rapid circles. They tend to amble about and feed on the glass and other surfaces.

[SuperProofer]

The ambling about and feeding on the surfaces is their normal pace.