It's going to depend on how high up your tank is. I couldn't use a tripod, as my tank sits too high. I just stand on a small step ladder to look down into the tank.
I use one of the Amazon basic tripods. Works great for filming for my YouTube channel and for taking pics. If I were to extend the head all the way up, and want to turn the camera toward the floor, I would recommend placing a weight (sandbag) on the leg cross-bars so that it doesn't tip over.
I have one of these C-stands for an overhead studio light but it should work for cameras too. Sandbag on one of the legs to counterbalance the camera/light.