Air circulation at this point is critical for your plants. An aquarium is pretty confined even with the top off. But it might work. I would try to find another solution if possible but it might still work. I know cats are plant killers so it is preferable to letting them become cat entertainment. Maybe rig a very small fan like a personal one 3-4" size. You might want to rig some kind of cover out of screen or hardware cloth or chicken wire. Maybe fashion a complete cover like and upside down box that covers all the plants so your plants are not enclosed with glass.
Bruce

Do you have a room can move them to where you can close the door to keep the cute kitty's out?

I vote for the kitties finding a new home! ;-) haha!

I agree, you need air circulation. Just get a little clip on fan and point it at the far wall of the aquarium. I don't think I would bother lining it with foil.

That said, I agree that I'd probably look for a better solution. I wonder if you dusted them with some hot chili powder (or even made it into a spray) if that'd deter the cats.

They actually had chili powder on them at the time this nibbling took place. i have a closet I may be able to put them in, I will look into that. Otherwise Ill find a small fan and roll the dice and hope it turns out well. Eventually they will be moved into the garage once it is consistently warmer.
Kitties arent going any where theyre my babies - I can get creative with seedlings if necessary

Let us know how it works out for your 'babies' when they get hot pepper powder in their eyes. Haven't you people ever watched cats clean their faces with their paws? They lick their paws then rub their face. I have cats...I grow hot peppers...I even make powder, but I'd never expose my cats to it. I protect the plants with chicken wire until they're planted outside and I grow wheat grass for the cats during the winter to chew on.
I also wouldn't want to pet a cat that had pepper powder on its fur, then inadvertently rub my own eye. What if it happened to a child?
I'm not trying to be harsh. I just get very upset when I see these posts about using hot pepper powder around animals/pets. Try some in your own eye and see how it feels(yes, I've done it while cooking and not on purpose).

Using an aquarium as a plant shelter is harmless. You don't need ventilation so long as the top of the aquarium is not covered. The only reason for folks having a fan blowing across their seedlings is to stimulate thick stems from a plant response called "thigmatropy". This is the name for an effect where plants alter their growth habits as a result of being touched. It was first noticed in greenhouses where plants next to the aisles were found to grow sturdier and healthier. The cause was workers walking down the aisle brushing against the plants. You can stimulate thigmatropy by rubbing your hands or a stick across the tops of the plants a couple of times a day or by placing a fan so it blows gently across the seedlings.

What you can do to achieve the same result is lift the cups out of the aquarium once a day and brush them back and forth a couple of times with your fingers. Other cautions are just general, be sure not to over water, make sure there is a hole in the bottom of the cup so excess water can drain, and be sure they are getting plenty of light. My recommendation is to measure your aquarium and then visit a pet store for a screen top. This would pretty much resolve your cat problem.

DarJones

Thanks for all the feedback, so far the kitties have left the aquarium alone but you never know when they will get a case of the crazies. On my next day off I will see if I can set everything up in the closet since that should also give me a little more room

I'd look for a wire mesh cover to use as an aquarium lid, the sort used when reptiles are kept in the aquarium. Check the local pet shop. That will make it harder for the cats to get in there.

There's a product called Bitter Apple which is a chew deterrent. It's harmless but tastes unpleasant. People do use it on houseplants, but I'd try one pepper plant first to make sure it's ok for the pepper. Some pet owners say their pets don't mind the taste, so it's a gamble.

I got some of that bitter apple spray. Dog loves it.
Bruce

That is kind of like the person who was thinking of using superhot peppers as a vole deterrent. I can see it now, one vole yelling to another "Hey everybody! Come to dinner! and its already been seasoned!"

DarJones

I would use a small fan. Not sure if a fan is required for seedling transpiration, but the confines of an aquarium may make it easier for fungi to get established. Air movement is always good for plants. It makes them stronger. Stagnant air can cause a multitude of problems.