About three months ago I added four Habrosus dwarf corys to a PFK/Arcadia 25l cube, planted with Crypts, Java Fern, etc. and yeast based C02.
Water changes are 30%weekly with the gravel hoovered at the same time.
All readings were fine (pH 6.8, Ammonia 0, Nitrite 0, Nitrate 20, temp 75) as were the corys for about three weeks.

First two died, then the following week one more, and finally the last one a week later.
I again tested the water but got the same results.

Before I order another batch, is there anything I might be doing wrong ?

TIA

Hi,

I've just joined (though have lurked for a while) and hope to learn more about Corys.

I have a Rio 400 community tank with 6 bronze, 3 albino, 3 peppered, and 1 panda (a rescue) along with 10 clown loaches, 6 angels, 1 SAE and a platy mulitude.
Most of the fish (CL's, angels, bronze corys) are over 4 years old.
The tank is heavily planted and gets pressurised C02.

I also have one of the PFK/Arcadia 25l tanks in which I had four dwarf corys, of which there is only one left
it has temp in the mid 70s, plants and yeast based C02.
I had the corys for about 2 months.

I know I'll get some good advice here to help me keep the next batch alive