Fabric skirts, attached with Velcro along the top, so you can easily access underneath but also remove and wash when needed.

Is this in a store? I need a bit more info and you need to be able to access things so provide a little more please.

^ agree with AiFL - black fabric will recede and keep attention focused on the tanks

Review your local safety requirements for electrical wiring near sources of water. Do you have an electrician scheduled to fix the dangling wires and electrical cords under the floor mats?

Great suggestions !!
Thank you all. Yes it’s a store

If you cover up the stands with curtains, small children in your store could go under the stands and play with the electrical wires where no one can see the children. I strongly suggest you do not use curtains. It would be much better to remove everything on the floor under the aquarium stands, use paint for the wood areas, and keep the floor spotlessly clean.

I agree with the suggestion to use black fabric. You could attach it at the top & that bottom horizontal metal piece with Velcro. You can purchase Velcro by the yard at fabric stores. By leaving it open on the bottom couple of inches it will help to keep the black fabric clean.

IMO the fabric will look tacky and I agree about kids . Why not some siple sliding doors almost like barn doors for easy access but loks preofessional

The cinder block-and-wood used in the middle picture looks to me like an accident waiting to happen because there is nothing actually holding it all together. I think a Unistrut frame similar to what is in the other pictures would be more sturdy. You should also have some type of flat top anchored to the top of the Unistrut frame -- don't just balance the tanks on the rails of the Unistrut frame. You can hold the wires in a Unistrut wire channel. As for covering the bases -- fabric curtains would not only look tacky, but they would be a hazard on many fronts -- a possible fire hazard, dangerous if kids start to fool around with them. You need to think of how to attach something like sliding cabinet doors (bypass doors like those used for closets) to the metal frames. The sliding doors don't even need to go to the floor, and it may be better if they don't -- jut anchor them somehow to the top and bottom to the metal frame. One thought also -- will sliding the doors cause the whole assembly to wobble? Is the frame anchored to the floor? Maybe I'm overthinking this, but since it is a commercial establishment, you have a lot of liability, and so perhaps the best idea is to get some on-site advice from a professional.

On second thought -- maybe fabric would work, if you made fabric panels (rather than "curtains") that fit tautly and could be attached to the metal frame with Velcro on all four edges. Glue one strip of Velcro to the frame and sew the mating piece of Velcro to the fabric panel. This could work as long as you don't need to access the area underneath the aquariums too often; it would not be convenient if you had to open and then re-seal the panels multiple times a day. But you do need to do a lot of work besides just hiding the equipment -- you need to deal with the electrical problems (extension cords, etc.); make sturdy bases; clean up the metal bases you have (assuming they are strong enough), etc.

Thank you all for the great ideas!