Using an extracted mesh from Sherlock Holmes, I created a functional aquarium, I tested it in my game Im not sure if it needs pets expansion or not and its not recolorable.
https://simfileshare.net/download/4010634/

Very nice! I love it.

Thank you ,Im a little concerned because its so high poly I havnt tried lowering it yet,I dont want to ruin the appearance. I might have to.

You could do a lower poly version and see if it still looks good, and if not just let people know the poly count so they can decide if they want it.

I took a peek in Blender and: the seahorses have undersides, even though they're a closed object where the backfaces can't be seen.
You can about half the polycount just by removing those
The normals are also a little rough.

You can select each seahorse with L and Delete Faces, then select them again and go to the Mesh > Normals > Reset Vectors to fix both of these issues.
11k to 7k polycount without affecting the appearance.

Thank you!

I put it back in blender and removed doubles this is what it looks like in workshop,not so good.
I will try your way just faces,keeping my fingers crossed it works,im thankful for the help advice is appreciated!

I hope it works! I'll take another look if it doesn't come out quite right.

it worked faces only the way to go thank you so much with it being in blender tho I saw some fixes I needed to do with the tank to line it up better.Thank you again!

Can't wait to see it updated, it is beautiful

ok I got the vertices and faces lower but im not happy with the glass part of tank its not good enough so even tho im sharing the download,I will be going thru piece by piece and redoing this I want it to look nice,and I noticed the pebbles inside of tank were not right.
download for the lowered polycount. https://simfileshare.net/download/4023236/

sharing this also a WIP. From sims 2 because EA didnt give it to us in sims 3.I will figure it out.