It's a 40g breeder tank on industrial shelving rated for 1200+lbs. Glass lid with an opening in the back for the canister filter lines. LED shop light and grow light laying across the top.
*I* know that it's most likely not a problem with cats and we could figure out a work around for the lights and maybe the opening (I liked the ventilation, would prefer not to close it all the way) There was an earlier incident with one of our cats who liked to sit on top of a smaller aquarium with a plastic lid. The cat was fine for about a year and then out of the blue when no one was looking tried to squeeze his big self onto the aquarium, crashed the lid down into the tank. Happened again when I thought I'd fixed it.
DH is not a big fan of fish really or any animal other than cats. He uses the cat tank crashes as the main excuse anytime I mention it.
I'm just gonna bide my time about changing the location. It'll happen eventually lol.
*I* know that it's most likely not a problem with cats and we could figure out a work around for the lights and maybe the opening (I liked the ventilation, would prefer not to close it all the way) There was an earlier incident with one of our cats who liked to sit on top of a smaller aquarium with a plastic lid. The cat was fine for about a year and then out of the blue when no one was looking tried to squeeze his big self onto the aquarium, crashed the lid down into the tank. Happened again when I thought I'd fixed it.

I'm just gonna bide my time about changing the location. It'll happen eventually lol.