I love Clown Killifish. But for some reason, in both my home tank and my office tank, I had not have much luck keeping them longer then 2-3 months. after a few weeks, I seem to start losing them one by one. Strangely, my other fishes grow well. I mean I have otos, Red Neons, Tucanos, Coral Red Pencilfish, Hastatus and I almost have no casualty from those. I notice they usually start by having clamped fins and start staying near the ground.

My tank is quite planted and I never could detect any ammonia whenever I test. I never seen Nitrite as well and both my tanks are over 6 months and quite stable. My Nitrate level goes between 20-40ppm with 50% water change every week. CO2 is high but i do not see any fishes at the top. CO2 indicator is light to lime green. Never yellow. I shift it around once in a while to see if there are any changes or dead zones. My water temp is always kept between 25-27. My water TDS is between 120-180 throughout the week. PH shows 5.8 to 6.4 depending on time of the day due to CO2 injection.

Any clown killies breeders has any tips? Or they just do not like CO2?