I have had 29 gallon tank with about 18-20 fish. Never had 1 fish die and parameters were great all along. Since then i decided to transfer all these fish to my 20 gallon hex tank so that i could use my 29 as a qt tank for my 60 gal fowlr tank. I know that i'm pushing it with this many fish in a 20 gal but i test frequently and do weekly siphoning. I havent lost any fish, but when i tested before my weekly water change, nitrates were over 100 ppm! Ammonia and nitrite were 0. So i siphoned and did about a 70 % water change and tested about 2 hours later nd nitrates came down to between 20 and 40 ppm. Just wondering if i should do like 20% changes daily until i get this down the rest of the way? I realize that nitrates are gonna be a battle with this many fish.