I will say outright up until a couple of months ago I had never built a fish tank stand. I hate, abhor, dislike and over all cany stand the wood stands.They do make decent fires though. I also need to say I have been building cabinets, shelving systems, libraries and buildings for many years. I built my fish room although its original use was a pressroom. As in offset printing. So I do know a little bit about carpentry both fine and construction grade.
First off the stiles (vertical pieces aka legs) should always be one continuous piece.
Racks should be lapped into the legs.
Glue should always be used. If it needs to be taken apart figure out how much can be glued and glue it. Screw the rest together.
Never use drywall screws. Although I like old school wood screws there are modern versions I would consider.
Never use drywall screws.
Looking at the stand from the front you should never, ever see end or side grain. Always and only face grain.
You should never see screw heads. Ever. Most of the cabinets I've built actually have no metal fasteners at all. It's all the glue and proper joinery holding up all the weight.
These aren't just my rules. They are pretty common in woodworking. There is a right way to do things. Make it right the first time then you won't have to do it again.
Sometimes I am my own worst enemy though. I enclosed a carport and built a bay window for the room along with an in wall 90 gallon. (I did build a stand for this one but it was hidden in the closet.) Neighbor came over to "inspect" and couldn't believe the work. Told me I was going too far overboard with it. No one tapes, primes and paint the drywall before putting panelling on. Yeah well I did. I redid the cabinets in that kitchen. Next door neighor starts going through by firewood pile and couldn't understand why 4 doors were in the pile. Simple I said. Can't you see the tip of the biscuit here? Told me I was too much of a perfectionist and to never ask him to build anything for me.
The library I am finishing up for myself has one section that is 54" wide. The grain for the back has to, absolutely must run vertical. Go figure what I needed to do. (I've got a lot of extra plywood left because of the grain direction)