I found it ran slowly on my phone and the tap controls aren't very responsive. I struggled to dash a lot more when my school got massive and the game appeared to lag quite a bit. My fish struggled to level and I could see pathways that bigger schools of fish made in the food.
Some schools seemed to be small enough for me to take out but would half my numbers. Trying to get the smallest fish to level gets harder as the school gets bigger. Also my fully leveled fish are so slow and often fall behind at the back, leveling my littler guys exposed like cannon fodder.
I love the concept and would love more artwork to look at. Cute little animations for leveling would be good at some point and maybe seeing the numbers of your school would be useful.
I can't wait to see what you do with these little fishy squishies.