Cute, but needs some serious balancing. By the time you have 6 slimeows you never need more because the pond takes WAY too long to restock, even with upgrades. And even if you do choose to upgrade the pond, the cost scaling is insane with very very little improvement. So it becomes way more cost effective to just get a bunch of Bigger Bowl upgrades and have like 6 slimeows and that's it.
The game also needs to be sped up, just in general. As in, accumulate money faster, and difficulty increases faster. Way too much waiting between upgrades. That is, unless this is meant to be an idle game, which it didn't seem to be since playing optimally has you reassigning slimeows between the pond and tower.