a cycle is advantageous and having a timer is vital, you way underestimate the imporance of it. First of most people prefer some plants in the tank, and for the plants a cycle is a must, plants simply won’t do well with more then 12 light hours.
Fish are not as obvious and the effects are less pronounced and can take months or years to take effect, it basically lowers their immune systems. When light is on fish is active, regardless if it’s tired, it’s natural. So you are exhausting your fish if you have lights on all day. Like with people weaker immune systems might lead you into old age or it might kill you in a year. It’s always good to mimic nature as much as possible.
I like your videos. My current 55L tank has fake plants, a large castle, a fake octopus with bubbles, a bubble volcano, black gravel, two platostomus, five neons, a couple of danos?, and too many multiplying guppies to count. The aquarium has black hair algae popping up on everything. I have not introduced anything new to the tank for months. I do tend to forget to turn off the aquarium fluorescent tube light that sits on top of the cover made for it. I removed the larger items the castle and octopus. I have changed the water with half tank changes. But now what? do I change to sand? one of the hang on the back pumps has failed. Do I goto a 100 Gallon Aquarium Fish Tank Canister Filter + 9W UV Sterilizer 370 GPH HW-303B? I do not have another tank to move the fish to and with the babies I don’t think I could catch them all anyway. HELP!