My hardest part to maintain the population is when the fish breed like crazy ( guppies , endlers , CPD , betta ) lol ... especially if the tank has a lot of hiding places for the fry ... like your endlers' tank is great with a lot of hiding places ... i only notice my guppies some weeks later when they become juveniles and am like, " euuh, did I have that much before ... I can't recall... " and then I would start to count one by one , but have so restart again on the 6th one as they are moving in all directions , then I would just give up on the 3rd attempt to check the population quantity ...
My hardest part to maintain the population is when the fish breed like crazy ( guppies , endlers , CPD , betta ) lol ... especially if the tank has a lot of hiding places for the fry ... like your endlers' tank is great with a lot of hiding places ... i only notice my guppies some weeks later when they become juveniles and am like, " euuh, did I have that much before ... I can't recall... " and then I would start to count one by one , but have so restart again on the 6th one as they are moving in all directions , then I would just give up on the 3rd attempt to check the population quantity ...
cheers from my fishroom channel in Chicago, where I'm a subscriber to yours and guilty as charged.