Female White Cloud minnows suddenly hiding when aquarium light is on

[Reg3]

Hi everyone! 

Just got back into keeping an aquarium a few months ago. I'm having a problem that I'm really stumped on.

I set up a 12 gallon long planted tank with 6 white cloud minnows(2 males, 4 females) and 4 red rili shrimp. One of the males decided to jump out of the aquarium last week so now only 5 fish. Plants are growing great and I check the water quality weekly. Everything has been fine up until a few days ago when I added 10 more red rili shrimp. No other changes. Suddenly the 4 females hide all day in one corner. The male swims around the entire tank as usual. They come out of the corner when I feed them but then quickly return to the corner. I've noticed that they swim all around the aquarium when the light is off. The weird thing is, the light has been there since day one. (3 months)  There has been spawning behavior in the past and all 4 females appear to be gravid.

Everything I can find online says to check the water parameters. Ammonia is 0%, Nitrites 0% , Nitrates about 5.0 ppm.

I just don't get why it's only the females behaving this way.

Any ideas are greatly appreciated. Thanks.

This photo is when I first set it up. The plants are much larger now.

 

[Biotope Biologist]

Yup sounds like breeding behavior to me. My females when breeding often strike off on their own and try to find spots in the plants. So I’m not surprised they’re being secretive. 

[Comradovich]

Mark's Aquatics on Breeding White Clouds pt. 1 of 2

The above video series may help you out. Idea isn't necessarily to give you tips on breeding so much as highlighting how they breed in case you've been sending some unintentional signals to them. They like to spawn first thing in the morning after an evening storm. So, if your light doesn't slowly ramp up intensity and the room is naturally dark... You'd be telling them it's "business time" every day when the light goes on.

Other ideas:

1. Maybe paint on or add a black film background so there's a definite "hiding spot" easily reachable from anywhere in the tank. May relax your females some.

2. Are they choosing the corner with the water sprite? (I think that's water sprite... could be guppy grass). They may be taking cover under some leaves. White clouds like being under plants, sometimes they'll even sleep on plants.

They may be stressed because the male is behaving like he's ready to breed and they don't feel comfortable enough in the tank to do that.