Corydoras aeneus suddenly hate all light?

[no_fin_nipping]

I had three Cory's from Wal-Mart last August, about 1" each. One died in 2 weeks. The others have been fine. The tank is fairly well planted (plastic) with slightly subdued lighting (1" masking tape on glass directly below tube). They would stay round the plants, but didn't totally avoid the light. I do water changes every 10-14 days of about 20%. The Cory's were hiding in a small cave and totally freaked out the last three cleanings. I added two new 1" Cory's today. Sometimes they come out of hiding if I turn the hood off and the room light is subdued. They are about 2" now.
Any ideas? They haven't discovered the babies yet, but they are doing well. Thanks.

 

[sarcare]

Corys aren't afraid of the light, they just can be skittish of movement outside of the tank. They like to have places to hide, but will come out to play. I have bronze corys as well, and they go through periods of activity and periods where they hide. Having more cories will make them feel more confident, but that might mean they continue to hide. How big is your tank?

 

[no_fin_nipping]

25 gallons. I know 25's may be a little deep for Cory's as I understand they prefer shallow tanks. The 25 is 20" deep, the same as a 55 gallon. A 29 is only 18" deep.
I have 4 tanks. Being pressed for space, they are all short and deep, at least somewhat. I have a 37 gallon with five Silver Dollars in my living room. If I had it to do over, I'd have a 38 gallon, because I'm certain the fish would be thrilled to have an extra 6" to swim and wouldn't miss the 2" less depth.
I have the 25 gallon with 4 Cory's, 6 Harlequin Rasboras and 4 White Cloud Mountain Minnows in my "home office". I used to have 6 white clouds, these fish cycled this particular tank four years ago. One didn't survive they cycle. One died about a year ago. The Rasboras are about 1.5 years old, and I never lost one. I know the tank is filled pretty tight.
I have a 20 long with eight long finned Blue Danios. I've been trying (unsuccessfully) to get them to breed for about a year now. They are in my basement in the area I work (small vinyl sign & t shirt business). Lastly, I have a 20 high tank with 8 Neon Tetras and 6 Blue Tetras (not a dyed fish, Boehlkea fredcochui) Interesting story how I got the Blue Tetras... I was shopping at Petsmart and I found one on the floor! He/she was still alive. There were 6 in the store. I bought them all. They actually gave me the one I saved for free! Never saw them before or since...

 

[bearskookum]

Boehlkea fredcochui

Hey I saw some Boehlkea fredcochui at my petsmart too...one was 2inches...most were 1.5inches....was wondering how you like them so far? Are they easy to keep?