Sealing wood in a home made cage

So after looking at a few cages online I think I want to build one to save some money and be able to make it the way I want it. After looking at a few posts on other people's DIY adventures I think I know most of what I need to know except for sealing the wood. I saw on one post someone used 3 coats of polyurethane to seal it. I'm just not sure how "Sealed" it needs to be since I'm branching out from aquariums so any info, tips or tricks would go a long way!
Thank you all very much!

Sent from my SM-S765C using Tapatalk

The reason you need a few coats of polyurethane is because the wood soaks it up the first few coats and you want it to become a smooth surface instead of the woods semi rough surface makes it easier to clean/disinfect

Also forgot to mention this you can use a wood stain to make it what ever color you want and give it a nice finish or match furniture in the room before putting on the polyurethane

I use Dry-Lock, from Lowe's.
~Beau

I tile the inside of my wooden vivs, super easy and cheap if you get the self adhesive vinyl tile made for bathrooms! and its water proof too (you know in case of spills)

I'm coming in a but late on this thread but first of all, hey Neenah from Pewaukee! I just got done building my DIY wood cage and I did plenty of research as well. I have to say I couldn't be happier than choosing "Varathane Water Based Polyurethane Semi-Gloss". 3 coats did the project good and there is no smell. The cage was usable in 48 hours I've got to say. I sealed it in the garage over the course of 3 days and had a fan on it.