Skunk Cories

[bikerfish]

Hi ALL
I put a thread on here the othe other day about my skunk cories , 1 died very quickly yesterday morning as he swam up to the surface , hung about there for a few seconds then as he went back to the bottom he just went onto his side and was dead by the time the poor little thing reached the sand
I checked him over when on a bit of tissue and he just looked healthy ? I have had them for roughly 4 months and they dont seem to be growing in size either , the other 3 are just sitting still in the corner.
I have done all my water stats and they are good , my 8 other cories are good and every so often laying eggs and always out and about and are fully grown , I bought all cories roughly same time .
I have substrate bottom , tank length is 38 inches with lots of plants and other hiding holes . I sit and watch the tank every day and no bullying by any of the other fish , the other cories amble over the top of them if they want to get past them , they seem in good health apart from this ?
As now there are only 3 of these do you think uping there group size to 7 will help them ? will they come and be more active ? the other cories are 4 bronze and 4 peppered .
Sorry for the war and peace but really need some advice
cathy

 

[bikerfish]

Hi sorry me again am I right and skunk cories grow to roughly 2inches as mine are only about an 1 inch ?
If I bought another 4 would then there be 7 just huddled in the corner ?
I have checked all fish again and no spots or any thing else which should not be there and gave tank its weekely clean which is going through substrate to get all bits up and any gases that might form under substrate, monthly clean of fluval 306 and changed 1 carbon which I change 1 every 2 weeks as there are 2 in this filter and have to be changed once a month, all other sponges are cleaned in tank water , I change 25% water which is made safe before going in tank weekely , then I clean substrate up of all bits weekely plus I clean substate of bits once in the week. temp is 24.2 maybe could be a little lower but just a tad ?
cathy
Please need some advice before heading to lfs to hunt down some skunk cories just in case I am adding to the problem