My sim lives a very busy life with a lot of kids, but lives a self-sustaining lifestyle that includes a lot of fish. It feels like I'm spending more lime cleaning out the tank from dead fish than she actually gets to eat. Is there an up-to-date mod that makes it so fish in aquariums don't die? I prefer to keep them in the aquariums cause at least then I know what's all in the fridge.

I believe you're looking for this: http://linna.modthesims.info/download.php?t=541635

Includes some tuning mods for both the bowl and tank, removing the need to feed the fish.